
ClaSS -' V: - ; -. r 



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COPYRIGHT DEPOSIT, 



VETERINARY MEDICINE SERIES 

No. 17 

Edited by D. M. Campbell 



FISTULA OF THE WITHERS 
AND POLL-EVIL 



BY 



Major L. A. MERILLAT, Sr., V. C, N. A., 

Editor, Department of Surgery, 

American Journal of Veterinary Medicine 



Published by 

American Veterinary Publishing Co., 

Chicago 






Copyright, 1917, by 

American Veterinary Publishing Co. 

Chicago 



DEC 15 1917 

©CI.A481012 



CONTENTS 

FISTULA OF THE WITHERS Page 

Introduction 7 

The Withers 13 

Pathogenesis 37 

Symptoms 57 

Treatment 67 

POLL-EVIL 

The Poll 105 

Pathogenesis 113 

Symptoms 121 

Treatment 127 



PREFACE 

There are several reasons why a manual on 
this disease should be a part of the veterinary 
literature of the day, the chief one being that 
fistula of the withers is a very prevalent disease 
of horses and thus exacts a big toll from the 
horse industry. Another reason for bringing 
it especially to the attention of readers of vet- 
erinary literature is the deplorable fact that 
its treatment has never been standardized in 
the veterinary profession. Almost all long 
known and common complaints of domestic 
animals of a serious character are handled ac- 
cording to definite plans, differing only in 
minor details. The many conferences of our 
teachers of surgery in association work, and 
the interchange of ideas made possible by the 
splendid periodicals which all progressive vet- 
erinarians now read, as well as the profusion 
of all kinds of literature that reaches everyone, 
has fortunately created a standard of treat- 
ment for nearly all of the more important ail- 
ments of animals. 

Not so, however, with fistula of the withers. 
Each seems to have his own plan of treatment 
and few, indeed, claim even a fair degree of 



G PREFACE 

success. Some are satisfied with caustics, oth- 
ers with lancing and irrigations, others with 
bacterins, while a few of the more daring pre- 
fer radical surgery that removes the causative 
elements. To these plans might also be added 
that of those who avoid fistula of the withers 
entirely, because of the discredit meddlesome 
intervention generally brings them. 

In every rural community of the Middle 
West the empiric finds a fruitful field for ex- 
ploitation in the many chronic, loathsome, half- 
cured fistulse of the withers found in the hands 
of owners willing to try anything after having 
given up in despair the various treatments that 
have failed. 

If this book will do no more than to inspire 
the veterinary practitioner to approach this 
ailment in a matter of fact manner and to han- 
dle it according to the common laws of modern 
surgical procedure; and if it will discourage a 
continuance of the half-hearted and always un- 
satisfactory methods in vogue, the effort will 
not have been lost. The Author. 

Camp Mills, N. Y., December, 1917. 



INTRODUCTION 

The disease known universally among Amer- 
ican veterinarians as fistula of the withers is 
described at much greater length in the follow- 
ing pages than has ever been done before in 
veterinary literature. Most of the authors of 
surgical subjects have dismissed this affliction 
with a few words, referring to it only incident- 
ally as an occasional complication of harness 
galls or other forms of trauma about the crest 
of the neck and withers, but always without 
dignifying it as an entity worthy of special 
notice. Its frequent origin in the bursa? on the 
thoracic spines of the region and its develop- 
ment independent of any apparent injury have 
only recently attracted attention. In fact, 
there are many who still entertain the opinion 
that it is but a complication of a contusion in- 
flicted by the collar, by rolling upon hard 
ground, by striking against a low stable beam, 
by rubbing against branches of trees while at 
the. pasture, or by bites from other horses. 
Without ever having been able to attribute any 
given typical fistula of the withers to a given 
traumatism, the theory of traumatic origin 
has been indifferently accepted as ample expla- 



8 INTRODUCTION 

nation of its cause. Thus years have been 
wasted in attacking the disease from without, 
giving only casual attention to the "interior" 
of the withers where it actually originates. 

We do not insist that the names "fistulous 
withers" or "fistula of the withers" are even 
good appellatives for the disease we are about 
to describe. On the contrary, a name less spe- 
cially pathologic in its meaning would seem 
more appropriate, since fistula is but a phase of 
the entity as a whole. The name, inappro- 
priate as it is, we retain because among our 
American readers it has been consecrated by so 
many years of usage that a change would lead 
to no better understanding of our exposition or 
argument. We retain the name, therefore, 
with the full knowledge that it is appropriate 
only for the latter stages of the disease and that 
the fistulae are but insignificant parts of the 
total pathogeny. 

Poll-evil, which we argue is but the same 
condition attacking the atlantal bursa, has, on 
the contrary, been more extensively described 
by writers throughout the history of modern 
veterinary science, and although it had been re- 
ferred to always as a complication of a trauma- 
tism in the earlier days, it was the first of these 
two diseases to be recognized as a bursitis. It 
has been designated as inflammation of the 



INTRODUCTION 9 

bursa of the ligamentum nucha? and by some 
writers as inflammation of the ligament itself. 
No one has thus far been able to prove its def- 
inite cause. Like fistula of the withers, ap- 
parently for want of an explanation based on 
demonstrable facts, it has always been attrib- 
uted to bruisings of the poll. 

While we do not entirely eliminate trauma- 
tism as the cause of some cases of poll-evil and 
some attacks of fistula of the withers, it has 
been our experience that when injuries are the 
cause, the wound or bruise is always apparent 
and the disease advances into the depths of the 
region by gradual stages from the initial focus 
deeper and deeper until the interior is finally 
attacked by the encroaching pyogenic process. 
In ordinary cases of both of these afflictions, 
the initial focus is always central, far down in 
the depths of the body where external violence 
can have but little influence. From this cen- 
tral location the disease as gradually advances 
in the outward direction in the ordinary case, 
as it does inward in the exceptional cases due 
to trauma. We have, therefore, no choice 
than that of describing both poll-evil and fis- 
tula of the withers as having two distinct caus- 
es, one a wound or bruise at the very surface, 
and the other, and commonest, as yet unknown. 

The prevalence of fistula of the withers and 



10 INTRODUCTION 

poll-evil we have found to be much greater in 
some localities than others. In some districts 
it is actually an equine scourge, while in others 
it is a rare occurrence. In southern California, 
for example, veterinarians seldom if ever see 
a typical fistula of the withers or poll-evil, while 
in central Illinois it is a veritable horse plague. 
In a recent conversation with an old horse 
breeder in the latter location the information 
was elicited that fistula was once as rare there 
as in California. Asked if he had any theory 
to advance as to the cause he seemed inclined to 
attribute most cases to influenza, and colt dis- 
temper, claiming that before these diseases be- 
came prevalent from the interchange of horses 
from shipping centers there were no cases of 
fistula of the withers. The rarity of shipping 
fever (influenza) in California, seems to add 
logic to these observations. 

But no matter what the cause may eventu- 
ally prove to be, the veterinary practitioner is 
today confronted with a serious disease of 
horses that he must endeavor to control and 
handle to the better satisfaction of horse breed- 
ers and the public. To fall short of meeting 
this requirement is one more adverse reflection 
on our ability to meet the demands of our 
growing live stock industry. To study, to ex- 
periment with, to strive to curb, and to analyze 



INTRODUCTION 11 

this affliction from every angle is therefore a 
worthy enterprise. It is at least a problem of 
the rural districts of the Middle West that is 
neither well handled, nor, so far as we can per- 
ceive, intelligently studied. 

The loss in horses in Illinois from fistula? 
alone reaches into the thousands. The loss to 
veterinarians from their helplessness in han- 
dling the cases and the discredit this state of 
helplessness brings to the veterinary profession 
are matters to be thoughtfully considered. 

The fact that the treatment of poll-evil is no 
longer an unsolved problem in veterinary sur- 
gery, and that this treatment, now standard 
for more than ten years, has proved as nearly 
universally successful as any surgical depart- 
ure can prove, and the further fact that this ail- 
ment differs from fistula of the withers only in 
matters governed by the location, should, it 
seems to us, have spurred veterinarians to re- 
sort to similar measures for handling both. The 
fact that the latter is located in a more com- 
plex region and requires an operation of great- 
er magnitude is, we believe, the only reason 
why no advance has been made in its treat- 
ment. 

Better surgery from every angle by which 
good surgery is judged (anesthesia, restraint, 
asepsis, hemostasis and wound treatment) 



12 INTRODUCTION 

will, we believe, eventually solve the problem 
of fistula of the withers in the same way that 
the much simpler operation has solved that of 
poll-evil. 



THE WITHERS 

The region of the anatomy called the withers 
has no well defined limits. The word "with- 
ers," therefore, while academic in hippology, 
is not usually found indexed in text books on 
anatomy. It is described as to shape in the 
study of types, but seldom as regards to its 
component parts, except in surgical anatomy 
— a branch of veterinary science that is as yet 
ill-developed. The horse judge studies the 
profile of the withers very carefully because the 
general appearance of any given horse depends 
a great deal upon its shape, its size and the 
measurements of its dimensions. The surgeon 
studies not only its shape and dimensions, but 
its constituent parts as well and their complex 
and disadvantageous arrangement from the 
surgical point of view. 

It is important to note that the withers may 
be high, low, narrow, broad, steep, sloping, 
long or short, and that any two or three of 
these characteristics combine to determine the 
various types of withers of different individ- 
uals. Graphic writers in describing equine 
types often use such terms as sharp withers, 
low withers, high withers, long withers, thick 



14 FISTULA AND POLL-EVIL 

withers, muscular withers, effaced withers, 
prominent withers, each of which, in addition 
to being descriptive in the study of profile, is 
equally suggestive in the study of etiology of 
affections of these parts and their surgical 
treatment. Each one of these characteristics 
contributes to a different etiologic factor as 
well as a different surgical problem. 

Boundaries 

The withers, although having ill-defined lim- 
its, may be said, for surgical study, to extend 
from the crest of the neck anteriorly, to a point 
posteriorly, where the dorsal spines descend to 
the level of the back. The second dorsal spine 
may be selected as the uniform anterior limit, 
but posteriorly no line can be drawn, because 
some withers end abruptly toward the level 
of the back, while others slope gradually to a 
more distant posterior point between the eighth 
and twelfth spines. The highest point is al- 
most universally at the fifth spine. The second 
dorsal spine may, therefore, be said to repre- 
sent the anterior boundary, the fifth spine the 
summit and any point between the eighth and 
twelfth dorsal spines the posterior boundary. 
In the downward direction, the withers may be 
said to descend to the bodies of the vertebra? 
mesially and to the distal border of the scapu- 



THE WITHERS 15 

lar cartilage, (cartilage of prolongation) lat- 
erally. With these boundaries as a point of 
departure, each structure comprising the with- 
ers might be studied per se, but from the sur- 
gical point of view its study en masse is of first 
importance. 

Component Parts 

The withers are composed of skin, fascia, 
muscles, ligaments, cartilage, bones, blood ves- 
sels, lymphatics and nerves. These are com- 
bined in a very complex and exceedingly disad- 
vantageous manner, since in situ they form a 
pyramid whose base is loosely arranged while 
the summit is, dense. The summit of the with- 
ers, under the skin, is composed of hard liga- 
mentous structures fixed firmly to the underly- 
ing bones. From this point, the layers of which 
the region is constituted separate from each 
other in the downward direction, permitting 
thereby a ready filtration of pus into constant- 
ly deeper and more inaccessible fortresses, and 
constituting a favorable field for the fruitful 
development and undisturbed sojourn of in- 
flammatory processes of a chronic character. 
The base of the pyramid is bounded laterally 
and ventrally by bones (the scapulae and bodies 
of the dorsal vertebra?) while anteriorly and 
posteriorly its component structures extend 



16 FISTULA AND POLL-EVIL 

without change of arrangement into the neck 
and back. Thus pus within the withers after 
filtering downward finds its only exit by trav- 
eling first in either of these two directions, and 
ultimately to the surface of the body at points 
remote from the seat of development. It is 
this complex arrangement that affords the im- 
pregnable intrenchment of pathological prod- 
ucts and that is responsible for the refractory 
character, the extreme seriousness and the un- 
varying chronicity of the disease known as fis- 
tula of the withers. 

The Skin 

The skin covering the withers possesses noth- 
ing unusual except the thickness of the subcut- 
em along the median line anteriorly where the 
heavy connective tissue of the mane begins. Pos- 
terior to the summit of the withers the skin is of 
normal thickness, but is separable only with 
difficulty from the aponeurosis of the fleshy 
panniculus whose fixed attachment is at the 
level of the fourth or fifth spine. Very often, 
however, the skin is the seat of scars superven- 
ing harness and collar injuries which fuse it 
into the underlying ligaments, fascia or mus- 
cles as the location mav determine. 

•J 

Panniculus Carnosis (Cutaneous Muscle) 

This muscular structure is a prominent feat- 
ure of the withers in that its chief attachment 



THE WITHERS 17 

is to the summit. Along the region of the with- 
ers its fibers, unlike those of any other part of 
the body, are vertical, extending downward to 
the proximal border of the scapular cartilage, 
where they find another fixed attachment. It 
is fused with and in fact may be regarded a 
part of the superficial fascia. As a structure 
to incise for invasions into the withers it may 
be so considered. Beneath the superficial fas- 
cia is another aponeurotic layer whose fibers 
are so arranged as to cross those of the tra- 
pezius beneath at right angles. This layer is 
of no special surgical importance. It is found 
only in a careful dissection of the region and is 
in no way influential in guiding pathological 
processes nor in shaping surgical procedure. 

The Trapezius 

The trapezius, excluding the fascia just 
mentioned, is the third layer of the withers and 
is really the first of the anatomical structures 
that must be reckoned with in the study of fis- 
tula. It is a triangular membranous muscle 
with its base upward running along the withers 
where its aponeurosis is attached to the supra- 
spinous ligament along the withers and to the 
ligamentum nuchas in the cervical region, ex- 
tending in all from the axis to the tenth dorsal 
vertebra. This triangular sheet-like structure 



18 FISTULA AND POLL-EVIL 

is bisected vertically with a central aponeurosis 
that is attached ventrally to the tuber spinse of 
the scapula. The anterior part is the trapezius 
cervicalis and the posterior the trapezius thora- 
calis. 

The Roof of the Withers 

Together with the skin, the fascia and the 
panniculus carnosis, the trapezius muscles may 
be regarded as the "roof of the withers. 33 

It is under this roof that typical fistula? of 
the withers develop and beneath which the 
atypical (traumatic) fistula? burrow in direc- 
tions of resistance less than that afforded by 
its dense, aponeurotic character. 

Rhomboideus Thoracalis 

The rhomboideus thoracalis extends from 
the spinous processes of the second, third, 
fourth, fifth, sixth and seventh dorsal verte • 
brae in a downward and outward direction to 
the mesial face of the scapular cartilage. It 
constitutes a thick, heavy curtain forming a 
"second or inner roof of the withers." Com- 
pared with the structures of a building, it 
might be said to be a curtain, sagging slightly 
in the middle, that extends from the comb of 
the roof to a point on the wall just beneath the 
plate beam. It is very loosely attached to the 



THE WITHERS 19 

mesial face of the trapezius laterally and to the 
longissimus dorsi ventrally and spinalis dorsi 
mesially and ventrally. Secondary abscesses 
of fistulas of the withers said to be located "un- 
der the scapula" are in reality located under 
this muscle, resting upon the longissimus dorsi 
but without any obstacle against the filtration 
of pus further down than under the upper part 
of the serratus dorsi. Pus seldom goes to a 
lower level because the latter muscle is at- 
tached firmly to the costal surface and above to 
the mesial face of the scapula, forming a space 
having a firm floor but without anterior and 
posterior walls. 

Rhomboideus Cervicalis 

The rhomboideus cervicalis is the forward 
elongation of the thoracalis, extending toward 
the head along the ligamentum nucha? as far 
forward as the axis. Its insertion is the an- 
terior part of the mesial face of the cartilage of 
prolongation. Its surgical importance lies in 
the fact that its ventral margin just in front of 
the scapula affords a point of invasion into the 
seat of a typical fistula ( Fig. 2 ) . It is also so 
closely related to the ligamentum nucha? that 
it seldom escapes attack from the morbid pro- 
cess, and when heedlessly sacrificed in resect- 
ing the ligamentum nucha? a pronounced de- 



20 FISTULA AND POLL-EVIL 

formation of the crest of the neck (ewe-neck) 
results. It may be said to reinforce the "roof 
of the withers" anteriorly. 

Other Structures Important Surgically 

The splenitis and the serratus cervicis are 
related to, in fact occupy, the anterior part of 
the withers. They lie immediately below the 
rhomboideus cervicalis and beneath the trap- 
ezius cervicalis. Their upper margins are re- 
lated to the former. Just in front of the car- 
tilage of prolongation they are very loosely 
attached to the rhomboideus and thus afford 
the portal for surgical invasion above referred 
to. They are thick, tuberous curtain-like mus- 
cles forming the bulk of the crest of the neck 
and on account of their thickness prevent 
facile direct invasion to the bottom of pus ca- 
vities which are usually located below this mar- 
gin at the level of the second dorsal spine. 
These two thick muscles, in short, form the 
lower part of the lateral walls of the pus cav- 
ity in fistula of the withers. The treatment of 
fistula of the withers would be a lesser problem 
if the pus cavity could be drained over the dor- 
sal margin of these muscles instead of through 
them. 

The longissimus dorsi. The longissimus dorsi 
at the withers occupies the space between the 



THE WITHERS 21 

rhomboideus and the complexus and spinatus. 
These three muscles may be said for descrip- 
tive purposes to fill in the angular space 
formed by the ribs and vertebral spines. 

Structures of Lesser Surgical Importance 

The complexus anteriorly and the spinalis 
dorsi posteriorly have no especial surgical sig- 
nificance, except that the former lies closely 
attached both to the lamellar and the funicu- 
lar portions of the ligamentum nuchas and the 
latter to the spines of the vertebra and are 
therefore implicated in disease processes, and 
besides being just two more structures to form 
channels for the burrowing of pus they in no 
way govern the course of surgical operations. 
In fact pus cavities that have formed beneath 
these muscles are inaccessible and disease of 
the structures between them (bones posteriorly 
and the lamellar portion of the ligamentum 
nuchas anteriorly) usually constitutes an in- 
curable condition. 

Viewed as a Whole 

The muscles of the withers viewed with the 
purpose of standardizing surgical procedure 
against fistula may be compared to an irregu- 
larly-shaped covered trough containing a 
longitudinal partition. Anteriorly the trough 
is walled by the splenius and the serratus cer- 



22 FISTULA AND POLL-EVIL 

vicis, posteriorly by the serratus thoracis and 
the scapular cartilage. Its floor is formed by 
the longissimus dorsi and its roof by the trap- 
ezius and rhomboideus. The central partition 
is constituted of the dorsal spines, spinalis dorsi 
posteriorly and the lamellar portion of the 
ligamentum nuchas covered with the com- 
plexus anteriorly. The bottom of the trough 
which must be reached for effectual drainage 
can be penetrated only with difficulty and the 
risk of inviting complications in structures not 
previously implicated. Furthermore, these 
muscles being in constant use in locomotion, 
respiratory acts and movements of the neck, 
tend to encourage the burrowing of pus into 
still more inaccessible recesses. 

Thus we find the musculature of primal im- 
portance in any study of fistula of the withers. 
It bounds initial abscess cavities in places 
difficult of access for drainage, they move upon 
each other and favor the distribution of puru- 
lent products into new fields, where secondary 
abscesses are formed, and it exhibits a remark- 
able trend toward fibrosis under the influence 
of the chronic inflammation of adjacent parts. 

The Ligaments 

The ligaments implicated in fistula of the 
withers are the ligamentum nuchas and the 



THE WITHERS 23 

supraspinous ligament, each of which is but a 
continuation of the other; the dorsoscapular ; 
and the interspinous ligaments, which curtain 
off the spaces between the spinous processes. 

The ligamentum nucha? is a strong, powerful 
apparatus composed of yellow elastic tissue and 
divided into two distinct parts: the funicular 
portion and the lamellar portion. The former 
which is of especial importance in fistula of the 
withers and poll-evil, extends from the occip- 
ital bone anteriorly to the summit of the 
withers posteriorly where it becomes white 
fibrous tissue and is continued over the spines 
of the sacrum as the posterior part of the sup- 
raspinous ligament. It is composed of two 
lateral halves each of which is heavy and 
flattened at the withers but gradually becom- 
ing round and somewhat smaller toward the 
occipital crest to which it is attached to the 
occipital protuberance. Two bursa? are 
found associated with this structure — one 
at the atlas and the other in the dorsal region. 
The atlantal bursa is the seat of poll-evil while 
the dorsal or supraspinous bursa is the location 
of typical fistula of the withers. The atlantal 
lies between the ligament and the dorsal sur- 
face of the atlas. The dorsal bursa is usually 
over the third dorsal spine but sometimes ex- 
tends backward as far as the crest, that is, over 



24 FISTULA AND POLL-EVIL 

the fourth and the fifth spines, and often as 
far forward as the second. It is at the level of 
the second dorsal spine where the causative 
center of most of the cases of fistula of the 
withers that we have examined carefully, were 
located. 

An important point to remember about the 
funicular portion of the ligamentum nucha? is 
its wide expansion posteriorly. Approaching 
the crest of the withers it extends in the out- 
ward and downward direction five to six inches, 
partly enveloping the rhomboideus and tra- 
pezius. This expanded portion is often the 
cause of recurrence of fistula after the main 
portion has been removed. 

It is surmounted along its course by the 
"pad of the mane" a structure composed of 
elastic fibers interspersed with adipose tissue. 
It is most abundant in the middle of the cervi- 
cal region and is best developed in stallions of 
the draft breeds. 

The funicular portion is a sheet-like par- 
tition dividing the superior cervical muscles 
into halves. It is composed of two layers 
attached loosely to one another by areolar tis- 
sue, and each layer is composed of two parts, 
anterior and posterior. The anterior part is 
thick and strong, attached to the funicular 
portion above and to the cervical spinous proc- 



THE WITHERS 



25 




Fig. 1 — Ligamentum Nuche of Horse. 
Note particularly the relation of the funicular portion of 
the ligamentum nuche to the atlas and to the spines of the 
thoracic vertebrae. Also the arrangement of the lamellar 
portion. (After Sisson.) 



26 FISTULA AND POLL-EVIL 

esses below. The posterior part is attached to 
the second and third dorsal spines and extends 
in the form of several digitations forward and 
downward where its brush-like fibers reach the 
spines of the fifth and sixth cervical segments. 
The fibers of the ligament are more spare than 
in the anterior part and sometimes do not even 
reach the sixth vertebra. Between the anterior 
and the posterior parts is a space of consider- 
able dimensions which especially in horses of 
good flesh contains a mass of fatty tissue. This 
opening is at the level of the extremity of the 
second dorsal spinous process and is the seat 
of typical fistula of the withers. It is the space 
where the sacculation of fistula begins. 

The supraspinous ligament is a structure 
composed of white fibrous tissue and extends 
along the dorsal region to the sacrum. It is 
the continuation of the ligamentum nucha? 
posteriorly. A careful dissection of this struc- 
ture fails to show that it begins as an independ- 
ent structure, as its fibers although they change 
in structure from yellow elastic to white fibrous 
tissue, are simply continuations of each other. 
From the surgical standpoint the supraspinous 
ligament and the ligamentum nuchas must be 
regarded as a single apparatus which changes 
in the character of its tissue at the crest of the 
withers. Over the crest it is a very thick, dense 



THE WITHERS 27 

structure and along its whole course backward 
it is attached firmly to the summits of the 
spines. 

The interspinous ligaments are thin mem- 
branous structures connecting the spines to one 
another and completely filling in the space 
between them from the bodies to the supraspi- 
nous ligament above, and thus completing a 
perfect partition between the two halves of the 
withers 

The dorso-scapular ligament is a reflection 
of the superficial fascia. It is a thick aponeu- 
rosis attached dorsally to the crest of the 
withers and passing outward and downward 
under the rhomboideus to the scapula and 
giving off layers which pass between the under- 
lying muscles — the longissimus and spinalis. 
At the crest it is really the aponeurotic origin 
of both the rhomboideus thoracalis and the 
splenius. 

The importance of these ligaments in fistula 
of the withers lies in the fact that they are 
implicated in the disease more commonly than 
the other component parts. Lying adjacent to 
the initial seat of the inflammatory process, 
and being but poorly nourished structures, they 
fall an easy prey to microbic products, becom- 
ing riddled with necrotic areas and thus pre- 
venting cicatrization of contiguous abscess 



28 FISTULA AND POLL-EVIL 

cavities. In poll-evil it is the anterior part of 
the funicular portion of the ligamentum 
nuchas that prevents healing, while in fistula 
of the withers it is the posterior end or its liga- 
mentous continuation — the supraspinous liga- 
ment — that is implicated. 

Cartilages of the Withers 

The cartilaginous tissue included among the 
component parts of the withers is found in the 
scapular cartilage (cartilage of prolongation) 
and in the semi-cartilaginous summits of the 
dorsal spines. 

The scapular cartilage which is attached to 
the vertebral border of the scapula is a wide 
expanse of hyaline cartilage about two inches 
wide extending from the cervical to the dorsal 
angle. It is thick at the attachment to the 
bone but becomes thin toward its vertebral 
border which presents an evenly rounded pro- 
file. Its mesial relations are the rhomboideus 
and the serratus ventralis and its lateral the 
trapezius and the attachment of the panniculus 
carnosis. To these muscles it is intimately 
related, being in fact imbedded in them. It 
forms the lateral wall of many of the secondary 
abscesses of fistula and its cervical angle and 
sometimes its vertebral border becomes impli- 
cated in the disease. By becoming divested of 



THE WITHERS 29 

its muscular attachments and perichondrium it 
plays the role of a foreign body and thus per- 
petuates secondary fistulous tracts, which, on 
account of the movement to and fro are very 
slow to cicatrize, even after the necrotic parts 
have been extirpated. 

Cartilage is found on the spinous processes 
of the third, fourth, fifth, sixth and seventh 
spines, but is most abundant on the fifth and 
sixth. To this cartilage is fused the fibers of 
the supraspinous ligament. When the liga- 
ment detaches from disease the cartilaginous 
ends lie bare and being soft often induce sur- 
geons to indulge in reckless curetting when no 
such procedure is indicated. Protruding like 
stumps into the bottom of the abscess cavity 
and being slow to separate from the viable 
bone beneath, these cartilaginous summits are 
exceedingly instrumental in delaying cicatriza- 
tion and a prolific source of recurrences. 

Bones 

The bones of the withers are the spinous 
processes of the dorsal vertebrae from the sec- 
ond to the point posteriorly where they reach 
the level of the back. They incline backward. 
They are thin at the anterior border, thick 
posteriorly and expanded dorsally to receive 
the attachment of the supraspinous ligament. 



30 FISTULA AND POLL-EVIL 

They increase in length from the first to the 
crest (the fifth) and then gradually diminish 
to the twelfth. Those immediately over the 
crest exhibit the cartilaginous ends above men- 
tioned. The increase in length is not symmet- 
rical, the second being almost twice as long as 
the first. 

They are connected to one another by the 
interspinous ligaments which complete an im- 
pervious partition between the two lateral 
halves of the withers. Laterally they are cov- 
ered with the spinalis and longissimus dorsi 
muscles. 

The spinous processes rank high in impor- 
tance in the study of fistula of the withers. The 
initial pathological process of typical fistula? is 
usually seated on the second and third seg- 
ments. The cyst which constitutes the first 
pathological change is attached to them and 
when opened often exposes their cartilaginous 
summits. In traumatic fistulae originating 
from superficial wounds, these processes often 
become the seat of a stubborn osteitis that 
descends into the cancellated tissue, sometimes 
as far down as the bodies of the vertebra?, 
creating very chronic if not always incurable 
conditions. 

The student of surgical anatomy should 
remember their length at the different points, 



THE WITHERS 31 

their cartilaginous summits, their backward 
direction, their connecting media and the con- 
tiguous musculature. 

Blood Vessels 

The withers receives its blood supply chiefly 
from two sources: the dorsal and the deep 
cervical arteries. Both are direct radicals of 
the brachial arteries, or more correctly speak- 
ing, the left one arises from the left brachial 
artery and the right one from that part of the 
same vessel on the right side while it still bears 
the name brachiocephalic artery. The origin 
of both is within the thorax. The dorsal 
enters the region of the withers through the 
second intercostal space and the deep cervical, 
through the first. Both of them leave the 
thorax near the bodies of the vertebra?. Their 
extra-thoracic distribution alone interests us, 
in surgery of the withers. 

Eoctra-thoracic distribution of the dorsal 
ai % tery. After emerging from the thorax 
through the second intercostal space it passes 
under the longissimus dorsi in an upward and 
backward direction, soon dividing into several 
branches. The largest anterior branch passes 
forward and upward under the splenius; 
extending branches anastomose with the deep 
cervical or are lost in the deep muscles of 



32 FISTULA AND POLL-EVIL 

the cervical region. The posterior branches 
pass upward between the dorso-scapular liga- 
ment and the rhomboideus and thence to the 
superficial muscles and skin. These radicals 
are normally small vessels, but in old fistula? 
they are often enlarged into arteries of a 
formidable capacity. The main trunk lying 
deeply in the base of the withers is seldom 
exposed in surgical operations. The variation 
in the distribution of these branches and 
especially the enlargement of some of them 
under the influence of disease make the study 
of the blood supply of the withers somewhat 
unsatisfactory from the surgical standpoint. 
There is always a pronounced difference in the 
amount of bleeding produced from incisions 
of exactly the same kind. 

The extra-thoracic distribution of the deep 
cervical artery. — Emerging from the first 
intercostal space, it passes upward and for- 
ward between the lamellar portion of the 
ligamentum nuchas and the complexus. It 
destination is the region of the poll where it 
anastomoses with branches of the occipital. 
Along its course along the neck it exhibits free 
communications with the vertebral and sup- 
plies by lateral branches the lateral cervical 
muscles. These lateral branches of the deep 
cervical which enter the splenius and serratus 



THE WITHERS 



38 




Fig. 2. — Deep Dissection of Neck of Horse. 
A. Deep Cervical Artery. (After Sisson.) 



34 FISTULA AND POLL-EVIL 

cervicis in the region of fistula of the 
withers are often enlarged into vessels of con- 
siderable dimensions. 

The vertebral artery. — The vertebral artery 
which emerges from the thorax in front of the 
first rib passes between the longus colli and 
the scalenus, and thence along the vertebral 
column through the foramina transversaria. At 
the axis it anastomoses with the occipital and 
along its course supplies numerous branches 
to the musculature, of both the dorsal and 
ventral cervical regions. The former anasto- 
moses freely with branches of the deep cervical. 

This artery is of no great importance in 
surgery of the withers on account of its deep, 
protected location. That its branches are 
capable of undergoing enlargement must, 
however, be considered in operations invading 
the region of the vertebral column, as for 
example in attempts to establish a drainage 
of abscess cavities resting on the bodies of the 
vertebrae (cervical fistula). 

The Nerves 
The nerves of the withers are both cranial 
and spinal. Sensation is supplied by the dor- 
sal branches of the thoracic and cervical spinal 
nerves while the motor supply is derived not 
only from those mixed nerves but also from 



THE WITHERS 35 

the spinal accessory — the eleventh cranial — 
nerve. 

The spinal nerves are seldom exposed to 
view in surgery of the withers and as they have 
a promiscuous distribution, loss of motor 
power is never observed from incision of the 
trunks or their ramuli. 

The spinal accessory being the chief motor 
supply of the trapezius and lying in a super- 
ficial position may be incised in making reck- 
less vertical incision over the lateral surface 
of the scapula below the scapular cartilage. 
Its division while not attended with any pro- 
nounced harm is inadvisable on the general 
grounds that large muscular areas should not 
be unnerved. 

The Lymphatic System of the Withers 

This may be said to include the intercostal 
nodes of this region and the prescapular nodes, 
together with their afferent vessels. 

The intercostal nodes are located at the 
intercostal spaces at each side of the vertebrae, 
and they receive vessels arising chiefly in and 
among the dorsal muscles. They are small in 
the normal state but in fistula of the withers 
they become larger and may even suppurate or 
become the initial seat of a secondary pleuritis, 



36 FISTULA AND POLL-EVIL 

The afferent vessels empty directly into the 
thoracic duct. 

The prescapular glands receive afferent ves- 
sels from the skin of the anterior part of the 
withers and also from the superficial muscles 
of the neck. The afferent vessels lead to the 
posterior cervical nodes and thence to the tho- 
racic duct. 



PATHOGENESIS 

There are two kinds of fistula? of the 
withers. One is the typical or idiopathic form 
and the other is the atypical, traumatic or 
symptomatic form. The first or typical has its 
origin in the development of a serous sac or 
cyst under the ligamentum nuchae at the level 
of the second or third dorsal spines, while the 
second or atypical is caused by an external 
wound that serves as a portal of entrance for 
microorganisms. In the first stages these two 
forms differ very materially in every respect 
but in the final stage they are alike in that both 
of them cause disease of the ligamentum 
nucha? or its backward extension (the supra- 
spinous ligament) and sometimes the spines of 
the vertebrae themselves. In short, each form 
finally plays the same havoc upon these struc- 
tures, although they have an entirely different 
pathology at the beginning. Fistula of the 
withers in the final stage might be properly 
called necrosis of the ligamentum nuchae or of 
the supraspinous ligament according to its 
cephalo-caudal location. In the typical form 
it is the ligamentum nucha? that is chiefly 
affected while the traumatic form, being 



38 FISTULA AND POLL-EVIL 

usually due to harness bruises, reflects more 
upon that part of the region occupied by the 
supraspinous ligament. The disease pro- 
gresses in many cases from one to the other of 
these two structures by extension of the dis- 
ease process in one direction or the other 
according to the initial seat. That is to say, a 
fistula beginning in a cyst at the level of the 
second dorsal spine may attack the liga- 
mentum nuchas above that level and then 
travel backward into the supraspinous liga- 
ment, while on the other hand a harness bruise 
may cause a disease of the supraspinous liga- 
ment at the level of the saddle seat that will 
travel forward into the ligamentum nuchas. 
In fact, all old cases have this dual involvement 
and often the spines beneath are found necrotic. 

The Typical Form 

To make our study more comprehensive we 
shall divide the development of this form of 
fistula into three stages, namely: The saccu- 
lar stage, the phlegmonous stage and the 
fistulous stage. 

1. Saccular Stage. This is the initial one. It 
has its origin in the accumulation of serosity 
upon or adjacent to one of the dorsal spines, 
usually the second. Beginning with this col- 
lection of serum, which is sero-fibrinous in 



PATHOGENESIS 39 

character, it gradually enlarges into a cyst of 
larger and larger dimensions until it becomes 
clinical by bulging at the surface of the base 
of the neck or at a point of least resistance 
adjacent thereto. The sac is at first very small 
and without any well developed limiting mem- 
brane but as it becomes larger the tissues react 
to the encroachment by forming a firm con- 
nective tissue layer around it and at the same 
time fibrin and cells attach themselves to the 
inner wall and thus pave it with a smooth 
carpet that completes a firm encapsulation of 
the liquid contents. The amount of connective 
tissue contained in the encapsulating structure 
varies with the chronicity of the process. In 
old, slowly forming cases the fibrous elements 
may form in large quantities, encroaching upon 
the capacity of the sac internally and gradually 
bulging exteriorly until the lesion is in fact 
more fibrous than cystic. Thus we have the 
large fistulae of the withers in which fibrosis is 
the dominating feature. This sac is uniformly 
related to one of the dorsal spines, usually the 
second, but sometimes the third and in rare 
cases the fourth or even the fifth. We have 
never seen a typical fistula of the withers orig- 
inate farther back. Those located on the sum- 
mit or further back are always of the other 
variety (traumatic or atypical) . The point of 



40 FISTULA AND POLL-EVIL 

predilection of typical fistula of the withers is 
stubbornly anterior to the summit of the 
withers — in the space where the spines decline 
abruptly into the cervical region. 

The sac forms slowly and without apparent 
pain or discomfort to the patient. We have 
found ample evidence post-mortem in subjects 
that have died from other causes that cysts of 
this character sojourn here without attracting 
attention. They are too small to bulge ex- 
ternally and cause no distress that would at- 
tract one's attention to them. These hidden 
cysts are sometimes the size of an egg and 
sometimes as large as a base ball, and when 
old are so well encapsulated as to prevent fur- 
ther development. Thus cysts may never de- 
velop into fistulas or, in other words, the sac- 
cular stage may never advance into the fis- 
tulous stage. The process is arrested by 
encapsulation and later the fluid content is re- 
absorbed, leaving no trace of its previous ex- 
istence. The resulting cicatrical tissue is lost 
in its connective environment. This process of 
arrested development, encapsulation and reab- 
sorption occurs also in clinical cases. Or in 
other words, a clinical case of fistula of the 
withers in the saccular stage that has never 
been exposed to extraneous microorganisms 
may disappear spontaneously. It is thus that 



PATHOGENESIS 41 

liniments and blisters applied to them often 
are credited with curative properties when, in 
fact, it was an inherent influence that operated 
to that end. 

The duration of this stage has been very 
difficult for us to determine. We believe, how- 
ever, that it is very irregular, that some cases 
develop very rapidly into clinical cases while 
others remain almost dormant for months, 
some disappearing entirely and some bulging 
slowly toward the surface. 

It is these slowly forming ones that develop 
so much fibrous tissue and thus change the en- 
tire aspect of the condition from cyst to neo- 
plasm. This occurrence seems almost sufficient 
reason to include in the classification a third 
form of fistula of the withers— the fibrous 
f orm — if the reader were not familiar with the 
remarkable aptitude of horse-flesh to form 
fibrous tissue from continued irritation. 
Edema, pressure, foreign body, feebly virulent 
infection, cold abscess, granuloma and other 
tumors in the flesh of horses cause the forma- 
tion of great volumes of fibrous tissue unlike 
that of any other animal. It is thus that a 
slowly forming fistula beginning in the depths 
of the neck becomes the underlying cause of 
the formation of new tissue in such abundance 



42 FISTULA AND POLL-EVIL 

as is seen in some cases of fistula long before 
infection has entered into the situation. 

Summarizing the condition during the sac- 
cular stage we find a sac containing a sero- 
fibrinous, sterile exudate, that may be large 
and surrounded by a thin capsule or small and 
enclosed in a very thick mass of connective tis- 
sue. Between these two extremes we find the 
intermediate varieties — for example, one the 
size of a child's head containing a quart of 
fluid and encapsulated with a fibrous envelope 
one inch in thickness ; another the size of a foot- 
ball with only a very thin wall; and finally, a 
rare case with a very insignificant cavity sur- 
rounded with a great volume of connective 
tissue. Pathologically all of these are similar, 
they differ only in the relative quantities of 
the different elements entering into their con- 
stituent parts. 

During this stage fistula is a benign disease. 
It is not as yet infectious. There is no syste- 
matic disorder. The patient suffers no appar- 
ent inconvenience. Its general health is 
undisturbed. 

Until now the process belongs to an order of 
pathological conditions no more understood 
than the growth of tumors. In fact, it re- 
sembles tumor and cyst formation in all 
respects. It is but cellular activity around a 



PATHOGENESIS 43 

fluid-containing cavity with the formation of 
new tissue influenced by an unknown stimulus. 
Henceforth, however, a change occurs; it 
passes into another entirely different stage 
through the intrusion of pyogenic microor- 
ganisms into the cavity. 

2. Phlegmonous Stage. This is the second 
step in the development toward a real fistulous 
condition. Inasmuch as there is no positive in- 
formation about the thoroughfare through 
which infection occurs we shall onlv venture an 

ml 

opinion that it is through the blood stream or 
lymph channels that the microbes reach their 
goal. There is, of course, the possibility that 
cutaneous bruises from the collar may afford 
an entrance avenue, but the fact that suppura- 
tion occurs in animals that have never been in 
harness and could not reasonably have sus- 
tained contusions of sufficient severity to cause 
subcutaneous infection, least of all, a still 
deeper infection within the cavity without any 
surface inflammation, leaves no doubt that at 
least a great majority of fistulas become in- 
fected from within. We have observed fistulas 
develop rapidly from the saccular to the phleg- 
monous stage following influenza, especially 
complicated influenza. In fact, fistula of the 
withers might with all reason be included as 
one of the sequelge of influenza. The large 



44 FISTULA AND POLL-EVIL 

number of remounts that develop this compli- 
cation after attacks of shipping fever confirms 
our observation of twenty-five years of city 
practice in this connection. The saccular stage 
of the disease affords a fertile field for the 
localization of the microbes in the germ-ridden 
body of the influenza patient. 

Once infected the patient falls sick and is 
henceforth in the siege of an enfeebling disease. 
The temperature rises to 102 degrees to 104 
degrees Fahrenheit; depression is pronounced 
and movements of the body are painful. Often 
the patient grunts as in pleurisy from the pain 
of turning the body. When these symptoms 
occur before there is any conspicuous surface 
swelling, there is indeed danger of overlooking 
the cause of the patient's indisposition. Or- 
dinarily the withers are hot, tumefied, radiating 
and painful on one or both sides. 

The course of this stage will depend upon 
the virulence of the infection, the fertility of 
the field afforded by the saccular stage, and the 
natural resistance of the patient. If the sac is 
small and well encapsulated and the infection 
feebly virulent, the process may be slow and 
even go on almost unnoticed, all of the while 
causing the formation of more fibrous tissue 
and making its inroad of destruction into the 
poorly nourished ligamentum nucha? and ad- 



PATHOGENESIS 45 

jacent structures, coming to the surface very 
slowly. It is, in fact, a cold abscess. Some 
months may elapse after infection has occurred 
before the abscess points at the surface, but all 
of the while pathological changes are taking 
place within. More connective tissue is formed 
and the necrosis of the ligament is extending 
forward and backward from the seat of the 
abscess which was originally the cyst. Soaked 
in this infected environment the dorsal spines 
become involved and separate from the soft 
structures attached to them, sometimes stand- 
ing out stump-like into the cavity until seques- 
tration occurs. Slowly the pus finds an exit 
at the surface of the body after burrowing here 
and there in different directions. The exit 
aperture is not uniformly located. It may 
sometimes appear at the summit of the enlarge- 
ment, but more often it is more remote, the pus 
having traveled between the different layers of 
fascia and muscular tissue of this complex 
region to places far removed from the initial 
hot-bed. We once traced a fistulous tract from 
the lumbar region forward along the longissi- 
mus dorsi, under the scapula to the level of the 
second dorsal vertebra. Other cases burrow 
backward under the cervical angle of the scap- 
ula and point at the highest point of the withers, 
leaving one to suppose that this is the original 



46 FISTULA AND POLL-EVIL 

seat of the trouble as in the traumatic forms. 
This likelihood of fistulse to point at or near 
one side of the summit has misled many a prac- 
titioner away from the actual seat of the causa- 
tive center. In short, the existence of the aper- 
ture in a posterior location is no indication 
that the case is not a typical one centered at 
the usual place, under the ligament at the level 
of the second dorsal spine. The aperture may 
come at different very remote points that are 
often deceptive. 

The average case is more acute. Given one 
with a sac containing a quart of fluid with a thin 
capsule and infected with virulent microbes 
that produce an acute inflammatory process, a 
channel is soon dissolved directly to the surface. 
Often pointing occurs long before there is much 
damage done to either the ligament and bones 
and if proper treatment were instituted, these 
might never become seriously involved. A cure 
could be effected without disturbing them. The 
cyst is developed, becomes infected and bursts 
at the surface without having done much dam- 
age. This is the most favorable of all the 
fistula? of the withers to treat surgically. On 
the contrary, if the process is slow and there 
is delay in pointing, and if no treatment is 
instituted to relieve matters, the disease slowly 
but surely encroaches into the adjacent struc- 



PATHOGENESIS 47 

tures and thus creates a less favorable con- 
dition. 

The duration of this stage like the former 
one is variable. If the infection is acute and the 
cyst wall thin, the abscess may ripen and burst 
in a few days, while on the other hand if less 
virulent and incarcerated in a thick wall, point- 
ing may be delayed for weeks and even months. 
When the abscess has once found a surface 
exit and has discharged its contents, the disease 
has passed into an entirely different stage, and 
for a time the systemic condition improves. 

3. Fistulous Stage. This is fistula of the 
withers. Heretofore the condition was fistula 
only in name, now it is a reality. Heretofore 
the course of the disease was guided solely by 
internal influences, now it is exposed also to 
secondary infections from without. It does not 
matter whether the pointing was spontaneous 
or whether an aperture was made artificially, 
we now have to deal with a deep-seated cavity 
that communicates freely with the outside 
where reinfection will continue to occur, and to 
make matters still worse the drainage is seldom 
good enough to evacuate the contents entirely. 
By remaining full of pus the cavity becomes a 
fertile field for microbian growth and cicatrizes 
very slowly. The pus-soaked walls of the cav- 
ity becoming carpeted with undulating indol- 



48 FISTULA AND POLL-EVIL 

ent granulations that encroach slowly on its ca- 
pacity and without always showing any ten- 
dency to complete the process of cicatrization 
because they must sprout largely from a poorly 
nourished matrix (the ligament) which now 
dies in foci here and there, and then sojourns 
only as a foreign agent to perpetuate the 
process indefinitely. The ligament, contrary 
to the generally accepted conclusion, is never 
found entirely dead, except in very old and ex- 
ceptional cases; it undergoes only focal 
necrosis at different spots, retaining enough 
vitality to delay sequestration, and all of the 
while sprouting out with indolent granulations 
over its viable zones. The granulations are in- 
capable of maturing into scar tissue because of 
the dead zones protruding here and there 
among them and because they are poorly nour- 
ished. Thus we must not suppose when we say 
that fistula of the withers is due to necrosis of 
the ligamentum nucha?, that the ligament is 
immediately dead and that as a dead object 
perpetuates the disease right from the begin- 
ning. Fistula on the contrary is due to the slow- 
ly dying process of the ligament, to its stub- 
born viability rather than to its death. Once 
dead, however, and separated from the living 
part, the cavity will cicatrize as soon as the 
slough is removed, encysted or dissolved, pro- 



PATHOGENESIS 49 

viding there are no secondary cavities that do 
not drain. 

During the fistulous stage of the disease we 
must reckon, therefore, with a slowly dying 
ligament, exfoliation of the ends of the spines, 
the secondary pus due to the burrowing of pus 
into adjacent spaces and the fibrosis that con- 
tinues to encroach upon the surrounding mus- 
culature. It is plain that these constitute a 
combination of very inimical conditions. There 
is also in addition to these, a chronic septicemia 
that slowly but surely undermines the general 
health and manifestly reduces the patient's 
vitality. The tracts leading from pus cavities 
to the surface apertures, to still further com- 
plicate matters, close up by cicatrization from 
time to time and thus pen up the pus again until 
it has burrowed out a new channel. During 
this occurrence the patient is again sick as in 
the phlegmonous stage, exhibiting pain, dis- 
tress in movement, fever and general malaise. 
Each attack of this kind leaves the patient more 
enfeebled and still further damages the withers 
by forming new tracts, more fibrous tissue and 
sometimes new secondary cavities. The disease 
ends in one of two ways: the common one is 
emaciation and death, and the other is chronic 
fistula, discharging limited amounts of pus for 
several years. Rare cases heal up spontan- 



50 FISTULA AND POLL-EVIL 

eously. Often the death follows an operation 
postponed too long, postponed until the patient 
is too weak to stand the ordeal of the extensive 
intervention needed to cope with the neglected 
condition. 

The location of the secondary pus cavities is 
varied. Backward between the scapular car- 
tilage and the dorsal spines as far back as the 
caudal angle of the scapula and under the 
rhomboideus, is a favorite location. Another 
place where pus commonly gathers is in the 
space under the scapula just above the insertion 
of the serratus thoracalis, and sometimes this 
same cavity is diverted also under this muscle 
and then extends downward over the costal sur- 
face as far down as the sternum. The most 
serious secondary cavity, however, is the one 
that seats itself in the cervical region on the 
bodies of the vertebrae on one or both sides of 
the lamellar portion of the ligamentum nucha?. 
This one constitutes what has been called cervi- 
cal fistula, a condition due to implication of the 
ligament anteriorly. When a large area of the 
lamellar portion is involved the neck tumefies 
on both sides and one or more tracts form to 
the surface, often as far forward as the middle 
third of the cervical region. This is one of the 
most hopeless terminations of fistula of the 
withers as the affected center is inaccessible to 




Fig. 3. — A Pronounced Fistula of the Withers. 



52 FISTULA AND POLL-EVIL 

any form of effectual treatment. The affected 
area of ligament is too extensive to extirpate 
and drainage apertures cannot be made nor 
maintained to any advantage. In short, 
cervical fistula is an incurable, hopeless con- 
dition. 

Still another location is the bodies of the 
dorsal vertebra* between the scapulas. Here 
the pus follows the spines downward and seats 
itself at an inaccessible place for drainage. 

The Atypical Form 

By atypical fistulas we refer to those of 
strictly traumatic origin. They supervene 
saddle, harness and collar sores and cutaneous 
contusions of various kinds, especially those 
due to a hard, continuous pressure or deep 
pressure. Most of them begin as a pressure 
gangrene of a small zone of the skin, the sub- 
altern and the underlying ligament. The mi- 
crobian floras of these lesions are the usual horde 
of staphylococci and bacilli that ordinarily in- 
fect wounds of horses. In one specimen taken 
from our clinic, Prof. Herzog isolated the 
Bacillus necrophorus in addition to the others, 
The ligament once attacked is slowly invaded 
farther and farther along its course and the 
underlying spines become implicated. That is. 
the disease once seated becomes progressive, 



PATHOGENESIS 53 

because the cavity, pointing upward, does not 
drain and the pus-soaked dead elements of the 
ligament remaining stubbornly attached to the 
living, favor the gradual onward march of the 
process of destruction. Those originating pos- 
teriorly travel forward into the ligamentum 
nuchas under the connective tissue of the mane 
and thus seat themselves at just the same point 
as the atypical form, the chief difference being 
the amount of bone involvement, which in the 
atypical form is always more pronounced than 
in the other. Beginning at the highest point 
of the withers from a serious pressure necrosis 
from the harness, this form is more prone to 
travel downward into the spines, ofttimes at- 
tacking two or more of them with an acute 
destructive osteitis that travels down toward 
the bodies of the vertebras casting off se- 
questra and fusing them together with a mass 
of connective tissue that is very slow to recon- 
nect itself to the surrounding integuments, 
even after the pathological process has other- 
wise terminated. 

The disease is most common in horses whose 
withers are thin of flesh from hard work and 
privation. The vitality thus reduced is a dom- 
inating etiological factor. The enfeebled tissue 
becomes the prey of the virulent infection in- 
troduced through and harbored by the harness 



54 FISTULA AND POLL-EVIL 

sore. The local dry gangrene called sitfast at 
the level of the collar seat is one of the com- 
monest causes as well as the initial lesion of the 
very gravest of fistula? of this kind. Here the 
thick, folded, hair-clothed skin and also the 
thick pad of connective tissue underlying the 
mane first undergo gangrene from collar pres- 
sure. Some of these sitfasts involve only the 
skin (superficial sitfast), others invade into 
the connective tissue and still others entirely 
through it, exposing the ligamentum nucha? 
beneath. From this exposure the process 
marches on along the course of the ligament 
and there sows the seed of a chronic state pre- 
cisely the same as fistula from other causes, 
and requiring the same remedial measures. In 
fact, it is our experience that fistula? of this 
origin are the most stubborn of all. 

Once seated in the ligament and bones, 
atypical fistula is identical with the one having 
its origin in a pre-existing cyst (typical fistula) 
and will henceforth undergo the same course of 
successive abscess and tract formation. Ab- 
scesses form, burrow to the surface, discharge 
for a time, heal up, gather again and burst at 
another point, and this chain of events may re- 
cur indefinitely. During the formation of a 
new abscess there is local pain, distressed move- 
ments, fever and a general indisposition just 



PATHOGENESIS 55 

the same as during the abscess formation of the 
typical form. There is, however, never as much 
fibrous tissue formed as in the other variety. 
Although the environs of the tracts and ab- 
scess are surrounded by fibrous tissue it is 
never so abundant. Voluminous fibrosis is an 
attribute only of slowly forming typical fistula. 
The secondary pus cavities of atypical fis- 
tula are more superficial than those of the 
typical kind, particularly during the early 
stages. These are often subcutaneous, some- 
times just under the superficial fascia and at 
other times simply under the trapezius, but 
later when the disease has become more deeply 
seated and has traveled anteriorly along the 
ligament, they may be found in the same deep 
locations as in the typical forms. On the 
other hand, it might be said here that these 
superficial abscesses do not occur except in the 
atypical ones, except when lancing or other 
improperly directed treatment causes them. 

The differences pathologically between these 
two forms might be summarized as follows : 

1. Typical fistula? originate in sterile cysts 
located on or adjacent to the second dorsal 
spine. 

2. The cause of typical fistula? is unknown, 
and the influence under which the cyst develops 



56 FISTULA AND POLL-EVIL 

a well defined limiting wall is likewise not un- 
derstood. It simulates tumor formation. 

3. Typical fistula? develop deep secondary 
abscess during the early phase of the phleg- 
monous stage, while atypical ones develop these 
only in the later stages. The early abscess 
cavities of the latter are superficial. 

4. Fibrosis, that is, the formation of fibrous 
tissue is more pronounced in the typical form 
and is never voluminous in the other. 

5. Bone involvement is more cercain and al- 
ways more extensive in the atypical forms. 

6. The toxemia is more pronounced in the 
early stages of the typical form, but in later 
stages both are alike in this connection. 



SYMPTOMS 

The initial stage of typical fistula of the 
withers develops unnoticed. As long as the 
cyst located in its mesial position is not large 
enough to bulge to the exterior of the body on 
one side or the other and before it has become 
infected with pyogenic microorganisms, there 
are no symptoms that would attract attention 
to the developing disorder of the region. 
Everything is normal in appearance and the 
patient suffers no apparent discomfort. Yet 
there is this initial stage of fistula of the withers 
to reckon with. How long the trouble is de- 
veloping at the center before there is any 
change in the profile of the region is not known. 
The fact, however, that we find on post-mortem 
examinations accumulations of a serous fluid 
at the level of the second dorsal spine varying 
from small sacs the size of an egg to that of a 
base ball enclosed in a feebly developed sac, in 
animals that were never suspected of having 
any such a condition and which died from other 
causes, is ample evidence that the disease exists 
a long time before the symptoms begin to ap- 
pear. Finally, however, the region begins to 
enlarge, first on one side and then on the other. 



58 FISTULA AND POLL-EVIL 

In rare cases both sides bulge simultaneously. 
The bulging may take the form of a circum- 
scribed spherical protrusion or it may be dif- 
fuse, extending evenly forward over the base of 
the neck and backward over the withers with 
its crest opposite the cephalic angle of the 
scapula or slightly forward from that points 
When both sides bulge from a diffuse enlarge- 
ment, the withers may appear enormous in 
width and elevation, sometimes to the extent 
of making the patient seem top-heavy. If the 
cavity is not artificially evacuated, nor other- 
wise molested, the enlargement may remain un- 
changed indefinitely. We have in mind cases 
remaining in the saccular stage for more than 
two years with no other changes pathologically 
than that of becoming less fluctuant from the 
development of its fibrous encapsulation, and 
not infrequently we have seen them disappear 
entirely. There is no way to predict accurately 
when any given case will suppurate. 

Finally, the great majority of cases pass into 
the phlegmonous stage ; that is, they become in- 
flamed from the invasion of microorganisms. 
This event is announced by local pain, radiating 
lines extending from the crest of the enlarge- 
ment, indisposition to move, grunting, fever 
and general depression. Cases that become in- 
fected before the cyst is large enough to bulge 



SYMPTOMS 59 

out the neck may prove puzzling in the absence 
of any pathognomic symptom. 

Then again we must differentiate (before 
suppuration unmasks the character of the ail- 
ment) fistula from other enlargements and 
growths in the region. Sarcomata and melan- 
osis may localize on the withers, and unless 
taken into account there is some danger of 
error in diagnosis. The former is, however, 
rare and the latter is seen only in white horses. 
A black work horse, submitted to the writer by 
Dr. D. M. Campbell, exhibiting a voluminous 
enlargement of the withers that had every re- 
semblance of the fibrosis of fistula, was found 
after an unsuccessful operation to be affected 
with a very large, deeply rooted sarcoma ex- 
tending downward into the thorax and affect- 
ing nearly the whole of one lung in addition to 
involving all of the structures about the 
withers. And again, the author once submitted 
a twelve-year-old horse, just turning white, to 
an operation for fistula only to find that the 
bulging was due to a melanotic tumor the size 
of a cocoanut, located in the splenius. 

It is also important to judge carefully recent 
swellings of the base of the neck and of the 
withers, as these might be mistaken for fistula. 
Horses frequently sustain severe contusions in 
this region, exhibiting either fluctuant or firm 



60 FISTULA AND POLL-EVIL 

swellings that are not easy to differentiate from 
the saccular and phlegmonous conditions as- 
sociated with the graver state preceding the 
fistulous stage. Subcutaneous and subfascial 
sanguinous sacs and hemotomata complicated 
or uncomplicated with infection, are the mosJ 
misleading of these lesions for which fistulas 
might be mistaken. The differentiation can 
never be made with certainty until the behavior 
of the swelling is noted, both before and after 
evacuating the contents. In fistula such swell- 
ings accentuate; in the others they subside, 
either with or without lancing. Besides they 
are always diffuse whereas the fistulas presents 
a spherical swelling in almost every instance. 

Although acute diseases running short 
courses, malignant edema and other erysip- 
elatous inflammations when attacking the 
withers may at first mislead the diagnostician, 
these are recognized by their acuteness and 
rapid advancement into adjacent regions and 
the serious concomitant toxemia. 

The early symptoms of the atypical form are 
likewise very often misleading. That any given 
harness sore will or will not end favorably is 
not always easy to determine. What might at 
first seem like a simple enough harness sore 
may finally prove to be the initial phase of a 
bad fistula. On the other hand, a badly in- 



SYMPTOMS 61 

flamed back may heal promptly. It is, there- 
fore, advisable to withhold an opinion about 
the seriousness of harness sores until the be- 
havior of the swelling and of the discharge 
can be noted. As a rule, however, a sore that 
exposes the ligament, and especially if the 
pain on palpation is excruciating and extends 
along the back some distance from it, is one 
to be viewed with suspicion. Painful subacute 
diffuse swellings extending forward over the 
summit of the withers are likewise incriminat- 
ing. Both of these circumstances indicate an 
extensive involvement of the ligament and un- 
derlying bones right from the beginning that 
is pretty sure to lead to a chronic inflammation 
of these structures far beyond the original 
focus — the harness sore. 

Sitfast of the collar seat, on the contrary, 
develops into fistula without these threatening 
external manifestations, and even without any 
perceptible pain. It causes fistula by rooting 
through the connective tissue of the mane into 
the ligament almost unnoticed. It is only when 
sequestration begins or when extirpation is 
attempted that the depth and the seriousness 
are determined. 

During this first stage of atypical fistula — 
which in this case is the phlegmonous stage — 
the patient is not stricken with illness as during 



62 FISTULA AND POLL-EVIL 

the same stage of the typical form. The trouble 
is thus far more like simple superficial abscess 
and is not attended with any serious toxemia. 
The toxins escape through the wound, whereas 
in the typical form they are pent up and ab- 
sorbed. It is only during the development of 
secondary abscesses that any serious systemic 
indisposition is ever observed. 

The symptoms of the fistulous stage. Fistula 
once a reality and beyond the developmental 
stage produces a clinical picture well known to 
everyone having had any experience with 
horses. Its exposition, if not also its descrip- 
tion, might seem unnecessary for the average 
reader, so well known are the manifestations 
of this fell and loathsome disease. 

It might be said for information of the 
novice that any chronic discharge of pus from 
or about the withers is fistula of the withers. 
It may be from a single aperture and unas- 
sociated with swelling or it may be from two 
or more apertures with voluminous enlarge- 
ment of the region on one or on both sides. 
The apertures may be located posteriorly, me- 
sially or anteriorly, on or near the median line 
or laterally at any point about the neck or 
shoulders. The most anterior location at which 
apertures are found is the middle cervical 
region and the most posterior location is the 



SYMPTOMS 63 

acnestis. These two extremes are, however, 
rare ones. Most of the apertures are found on 
or about the level of the withers and base of the 
neck. Ventrally pus sometimes burrows sub- 
cutaneously over the lateral face of the scapula 
and points at the level of the shoulder joint 
and more commonly a few inches above that 
level. The amount of pus discharged varies 
with the size of the cavity. After lancing, 
after the first spontaneous bursting or after a 
secondary abscess has been evacuated arti- 
ficially or otherwise, the discharge is sometimes 
very copious, overrunning the sides of the body 
as far down as the foot and by dessicating en- 
crusts itself thickly over the whole shoulder 
region and forearm. The discharge finally 
moderates and may even cease entirely pend- 
ing the formation of a new abscess and new 
aperture often on the opposite side or at some 
remote location on the same side, causing the 
same loathsome condition all over again. 

In the meantime the patient loses flesh and 
is unthrifty in general appearance. The coat 
is dull and uncouth, the ribs and skeletal angles 
become visible, and the reduced vitality be- 
comes more apparent. It is only the patient 
that is well groomed, well fed and well attended 
as to its infirmity that remains in good con- 
dition. The neglected subject sinks rapidly 



64 FISTULA AND POLL-EVIL 

into a still lower state of depression and may 
even die from chronic septicema. Operated on 
in this enfeebled state fatalities are of common 
occurrence. 

The profile of the withers during the course 
of the fistulous stage varies in different cases. 
Some are tumefied on one side, some on both, 
usually from fibrosis but also from common in- 
flammatory swellings which subside with each 
pointing of the abscess. Each aperture leaves 
a tell-tale scar and a denuded zone beneath 
where the discharges have destroyed the hair 
follicles. Where caustics, strong blisters or 
strong chemical irrigations have been em- 
ployed this marring is still more pronounced 
(see Fig. 4). 

Where the disease was left to run its own 
course, or was treated by only palliative meas- 
ures, the withers, neck and shoulders are left 
riddled with these indelible blemishes, and 
often through extensive sloughing of the liga- 
mentum nuchas the neck drops down in front 
of the withers into a permanent deformity 
(ewe-neck). 

In other cases the spines at the summit of the 
withers having lost their ligamentous covering 
protrude beneath the imperfectly regenerated 
integument and thereafter become the seat of 
sores from the harness and saddle that are diffi- 



SYMPTOMS 65 

cult to heal. At the sides of the neck just in 
front of the cephalic angle of the scapula the 
permanently enlarged musculature covered 
with denuded skin likewise chafes from the 
collar and thus proves a constant annoyance. 
Marred and sore-ridden, the subject is un- 
salable and ofttimes almost useless. 



TREATMENT 

The assertion that all fistulse of the withers 
might, to the best advantage, be submitted to 
a uniform (standard) method of treatment is 
a paradox. It is a paradox because such a 
statement at first thought apparently false is 
after all entirely true, as the treatment needs 
to vary only in regard to its details. The same 
general principles of management and treat- 
ment may be laid down for all of them, no 
matter from what source they originate, the 
course they may have taken, or the stage in 
which they are found when submitted for the 
surgeon's deliberation. 

That certain fistulse of the withers do some- 
times yield to lateral lancings and irrigations 
is not denied, but that the great majority surely 
but slowly develop into grave, enfeebling, in- 
curable and often fatal afflictions in spite of 
such treatment is equally true. 

It is, therefore, evident that prompt treat- 
ment of the radical sort is indicated at an early 
stage and before the infections of extraneous 
origin have done a widespread damage to the 
ligaments, bones and muscles, and before pus 
has burrowed into the inaccessible recesses of 
this complex region. 



68 FISTULA AND POLL-EVIL 

It does not matter whether the condition has 
been caused by an abrasion or has originated in 
a cyst of the dorsal bursa, procrastination is 
inadvisable. 

We have found, however, in the cases of typi- 
cal fistula? that the evacuation of the contents 
of the sac one week before the radical operation 
is performed, is good practice, because it forti- 
fies the tissues against post-operative infections 
of a grave character. Where strict aseptic con- 
ditions are maintained in the operation and 
the patient has skillful after-care, this precau- 
tion is not as essential as when careless methods 
prevail or when the after-care must be con- 
signed to untrained hands. 

It is, therefore, recommended, as a routine 
measure in field practice, to lance the cyst, 
evacuate the liquid and fiocculent contents and 
then submit the sac to casual irrigations one 
week to ten days before operating. 

In the case of old fistulas originating as 
cysts and which have become infected from 
any source or in the traumatic variety having 
either superficial or dee]) pus accumulations, 
lancing one week before operating is likewise 
helpful in that surgical shock is modified and 
there is less soiling of the surgical wound with 
pus during the operation. 

These suggestions need not be laid down as 



TREATMENT 69 

absolute laws, but it is advisable to follow them 
where it is desired to take advantage of every 
helpful influence. They are most important 
in subjects enfeebled from hard work or pri- 
vation and when from any cause a clean opera- 
tion and good after-care cannot be carried out. 

External applications such as liniments and 
blisters we do not recommend. They only 
complicate matters by irritating the skin and 
encrusting it with dried excretions difficult to 
remove in preparing the field for operation 
later, and so far as we have been able to de- 
termine they do not in any way influence the 
course of the disease within. Occasional cases 
abort in the cystic stage but this trend is spon- 
taneous and is not hastened by local applica- 
tions, and it is by no means certain that the 
decrease in the size of the enlargement is per- 
manent. Our observations indicate that at 
least some of these rare cases recur and finally 
burst to the surface. 

As regards the application of caustic chemi- 
cal substances into the tracts we doubt if there 
is any charlatanry, ancient, medieval or mod- 
ern, that savors more of cruelty and malprac- 
tice. The caustics — arsenic, copper sulphate, 
lye, corrosive sublimate, caustic lime, zinc 
chlorid, etc., after dissolving in the albuminous 
secretions overflow the surface of the body, 



70 FISTULA AND POLL-EVIL 

cause severe pain, prolonged discomfort and 
permanent blemish. Often large patches of 
integument slough away ( Fig. 4 ) . 

The only beneficial effect of caustics is the 
widening of the aperture and tract for drain- 
age and since this can be accomplished better 
and without discomfort by other means the one 
argument in their favor loses force. 

The treatment of fistula of the withers which 
in our hands has given the best results is 
prompt, thorough, surgical intervention. Our 
operation of choice and which is hereinafter de- 
scribed consists of a median line incision ex- 
tending from the crest of the withers forwards 
six to twelve inches and downward through the 
skin, the pad of the mane and then between the 
two halves of the ligamentum nucha? into the 
space beneath lying over the summits of the 
second and third thoracic vertebras. This is 
followed by a resection of such parts of the 
ligamentum nuchse as are thought to be harm- 
ful and then by making lateral drainage 
apertures from the bottom of the cavity to the 
surface of the cervical region into which a 
perforated drainage tube is inserted. 

Radical Operation for Fistula of the Withers 

Preparation. — As the procedure is one of 
some magnitude, attended with all of the dan- 




Fig. 4. — Effects of the Use of Caustics. 
This mule was treated for a typical fistula of the withers 
by the injection of concentrated lye. Discharge from the 
wound occasioned sloughing of the skin over large areas. 



72 FISTULA AND POLL-EVIL 

gers of major operations, it is essential to in- 
vestigate carefully into the patient's physical 
condition. Weak, emaciated, enfeebled sub- 
jects should be given a preparatory treatment 
that will tend to build them up in strength and 
vigor. This may consist in evacuating and 
irrigating large abscesses, cleaning them up 
over the soiled shoulders, grooming the body, 
good feeding and any general good care that 
will improve the health. The week or two re- 
quired for such preparatory treatment is not 
lost, since the improved health before the op- 
eration will shorten the duration of the period 
of post-operative convalescence, and will re- 
duce the rate of mortality which in enfeebled 
subjects is bound to be high on account of 
shock and the magnitude of the invading 
wound. Large wounds cannot be made in the 
bodies of an animal with impunity; in en- 
feebled subjects they are positively disastrous. 
Infections run riot in them and without ef- 
fectual resistance toxemias are fatal. We, 
therefore, advise against the operation in sub- 
jects not physically fit to stand the ordeal. 

Dieting is also essential as a preparatory 
step, as no animal may be safely cast and sub- 
mitted to a severe surgical operation with its 
alimentary canal filled with ingesta. This is 
especially the case with subjects to be anesthe- 



TREATMENT 73 

tized, with chloroform or narcotized with 
chloral. 

Preparation of the Field. — Scraping off the 
dried pus encrusted over the shoulders, wash- 
ing the skin with soap and hot water must pre- 
cede the attention to the field itself, as other- 
wise no effectual cleansing of the withers for 
surgical work would be effectual. Preferably 
this should be done on the day preceding the 
operation, and to prevent further soiling the 
shoulders might be annointed with vaseline. 

The hair over the withers and on each side, 
down no less than ten inches, is clipped and if 
possible shaved. The mane is clipped off well 
forward over the seat of the collar and the re- 
maining mane is braided to prevent its tufts 
from dangling into the wound as well as to 
keep it free from pus during the after-treat- 
ment. 

A good ablution with brisk friction of mer- 
curic chlorid in the dilution of not less than one 
part to five hundred is much the best prepara- 
tory disinfection of the skin along the line of 
incision. The field might in addition be 
painted with tincture of iodin. Shaving the 
mane hairs especially on the neck where the 
skin is folded transversely is difficult and very 
tedious as the folds are closed while the head is 
erect and as a painstaking shaving process pro- 



74 FISTULA AND POLL-EVIL 

longs the duration of decumbency we have in 
our recent operations been satisfied with clip- 
ping. By using the curved scissors these 
coarse hairs, even those between the folds can 
be trimmed away. In order to conserve the sub- 
ject's strength by shortening the duration of 
the operation proper it is, however, preferable 
that all of this cleaning up process and disin- 
fection be done in the standing position. By 
standing upon an elevation in a place where the 
patient's movements can be controlled and by 
twitching the nose, a more thorough cleaning 
can be given in the standing position than after 
the animal has been cast. When the body lies 
flat on the mat, ground or even the operating 
table, the sides of the withers are less accessible 
for clipping and washing, and besides when 
this is postponed until the subject is down, the 
ground under and about the withers becomes a 
disagreeable place to occupy while operating. 

Anesthesia. — Chloroform anesthesia is much 
the best, although narcosis with chloral hydrate 
administered no less than one hour before 
casting will answer when the retinue lacks a 
satisfactory anesthetist. 

For this purpose we administer per os, pref- 
erably as a drench twelve drams of chloral 
dissolved in one quart of warm water. Cannabis 
indica intravenously, chloral in the peritoneal 



TREATMENT 75 

cavity or morphin hypodermically may be 
substituted, but in our hands these agents have 
been greater disappointments as surgical nar- 
cotics than chloral hydrate, which, given as 
above described on an empty stomach, always 
produces some measure of blunted sensibility 
that facilitates the control of the patient if it 
does nothing more. 

When chloroform anesthesia is used, every- 
thing is made ready before it is administered in 
order to shorten the duration of unconscious- 
ness to the minimum. 

Restraint. — The standing position even with 
the best stocks is by no means an adequate 
restraint for effectual work. The lunging sub- 
ject is in danger of injury and the movements 
of the neck prevent accuracy of technic. The 
standing position answers well enough for lat- 
eral incisions, such as may be required to evac- 
uate abscesses preparatory to the operation, 
but when the center of the withers must be in- 
vaded for the purpose of resecting a necrotic 
ligament or of perforating the cervical muscles 
for drainage, the control must be complete — 
perfect. 

The preferable method is rope restraint, with 
all fours folded securely under the body. The 
collar part of the rope must pass from breast 



76 FISTULA AND POLL-EVIL 

to back instead of encircling the neck. The 
collar seat must be free from obstacles because 
the incision crosses it and besides a rope en- 
circling the base of the neck would interfere 
with making the lateral apertures for drainage. 
A rope whose collar is large enough to drop 
under the sternum while its backward part will 
rest in the middle of the back is best adapted 
for the purpose, as it leaves the withers unob- 
structed. The two free ends of the rope en- 
circle the pasterns of the hind legs and then 
pass forward into the collar. When the horse is 
down the hind legs are drawn into a securely 
flexed position. The fore legs are tied securely, 
flexed with straps or preferably with cords. 
Thus secured the body of the anesthetized or 
narcotized sub j ect can be rolled into the ventral 
position where it can be blocked with sacks or 
held by several assistants. The operator stand- 
ing on the right side is now in a splendid posi- 
tion to proceed. 

On the operating table which brings the body 
up to a position comfortable enough to invade 
the withers mesially there is the objection that 
the under side is not very accessible for making 
the lateral apertures. Although this objection 
can be overcome by rolling the head and neck 
downward and backward there is by no means 
the same opportunity to perforate the cervical 




-pig. 5.— Tumor forceps of a serviceable pattern for fistula 
operation. The style of the jaws in tumor forceps is a mat- 
ter that should be carefully noted in purchasing such an in- 
strument. For instance, some vulsellum forceps are so de- 
signed that the incomplete curve of the jaws together with 
their slender and weak construction makes them too delicate 
for much veterinary surgical work. The instrument illus- 
trated above is designed so that with them a firm grasp of 
tissues is possible and a secure hold is insured. 




Fig. 6. — Drainage Tube and Inserter. 
By means of the drainage tube inserter it is possible to in- 
troduce a rubber drainage tube with a minimum of invasion 
of sound tissue. This, in many cases, is an important fac- 
tor, as it prevents needless contamination of uninvaded parts, 
limits the area of infected tissue and possible resultant com- 
plications and greatly facilitates the execution of this part of 
the technic. Hemorrhage is reduced to a minimum, opera- 
tions are completed with dispatch and, therefore, with less 
danger of surgical shock when these appliances are employed. 



78 FISTULA AND POLL-EVIL 

muscles as when the subject is tied in ropes and 
rolled into the ventral position. 

Instruments Required. — A good strong and 
well sharpened scalpel; a probe pointed 
bistoury, two large tumor forceps, an assort- 
ment of hemostats, a drainage tube inserter, 
a perforated rubber drainage hose, a large 
needle threaded with strong material. There 
will be needed in addition to the usual basins 
for antiseptics, a separate basin containing an 
abundance of oakum, which is to be used for 
packing the cavity immediately after the op- 
eration has been completed. We use clean 
oakum soaked in a strong solution of mercuric 
chlorid for this purpose and with this we place 
the threaded needle to prevent its thread from 
becoming entangled among the instruments 
while operating. 

A yard of muslin or burlap will also be 
needed to cover the withers as a protection 
against soiling after the patient is returned to 
the stable. 

Technic. — Standing on the side of the 
patient now rolled in the ventral position, 
facing toward its head, the operator plunges 
the scalpel deeply into the middle of the neck 
at a point varying from six inches to twelve 
inches in front of the crest of the withers, and 
then draws it backward as far as the crest — the 



TREATMENT 79 

full depth of the blade. The variation in length 
of the incision is necessitated by the difference 
in the size of the patient, in the thickness of 
the skin and underlying pad, and also by the 
size of the tumefaction. In a small horse, for 
example, having only a small rounded sac 
bulging at one side, an incision six inches long 
will be found anrple, while in a large "meaty- 
necked" draft horse having an enormous swell- 
ing it must be at least twelve inches long. 
Otherwise the walls of the wound cannot be 
parted enough to give a good access to the bot- 
tom of the cavity for inspection and for resec- 
tion of diseased parts of the ligament. We 
aim in the first stroke of the knife to incise 
the skin and underlying pad from end to end, 
that is, from the point decided upon anteriorly 
to the crest of the withers. For descriptive 
purposes this may be designated the first step 
of the operation. 

In the second step each of the edges of this 
large wound is grasped deeply with the tumor 
forceps. An assistant should hold one of the 
forceps and the operator the other By draw- 
ing the wound apart with some force the bleed- 
ing now spurting from many small vessels is 
immediately controlled and after widening it 
out, a good view of the bottom is obtained for 
the next incision. The scalpel is now plunged 



80 FISTULA AND POLL-EVIL 

between the two halves of the funnicular por- 
tion of the ligamentum nuchas into the loose 
tissue beneath and drawn backward again the 
full length of the wound. This opens the cen- 
tral cavity which in typical fixtula? is uni- 
formly located at the level of the second tho- 
racic spine. 

The third step. Blood is now hurriedly wiped 
out, the forceps are drawn upon with force to 
reduce the flow and the large spurters are 
snapped up in hemostats. It is not, however, 
advisable to devote much time to this hemo- 
stasia unless efforts at its control promise to be 
promptly effectual, since futile attempts de- 
lay the work and add to the blood loss. If the 
operation antedates the formation of pus, that 
is, if the contents are still sero-flbrinous, there 
is no occasion for doing anything else than that 
of now inserting the drainage tube, while on 
the other hand, if there is pus and the ligament 
is found more or less riddled with disease, re- 
section of the diseased parts is now under- 
taken. In very old cases it is entirely removed, 
in more recent cases its mesial parts are sliced 
off. In this step we also in many cases en- 
deavor to resect the wall of the sac, or as much 
of it as is accessible for hurried removal, leav- 
ing the ligament untouched. This, of course, 
is possible only where the sac is small and on 



TREATMENT 81 

account of age has a well defined limiting wall. 
It is often possible in many cases to resect the 
sac and then heal up the wound under aseptic 
conditions without drainage. More often, 
however, the region is invaded with infection 
of long duration and exhibits necrotic areas 
which must be removed. For example, if the 
ligament is found carueted with undulated 
granulations and is seen to exhibit necrotic 
spots or is riddled with pus tracts, it should be 
entirely removed The resection is effected by 
cutting it off anteriorly, grasping the end with 
a tumor forceps and then dissecting it in the 
backward direction to the posterior commis- 
sure of the wound. This is done on both sides 
or only on one side according to the condition 
in which the ligament is found. When not too 
firmly fixed into the adjacent connecting tis- 
sue it can often be torn out with the tumor 
forceps. 

The bones beneath are left severely alone. 
Trimming with bone forceps or curette is not 
recommended. Spontaneous exfoliation is de- 
pended upon exclusively. We have found that 
meddling with the spinous processes is a harm- 
ful practice. The exposed curetted ends be- 
come open channels for the descent of new and 
deeper inflammatory processes, when later dur- 
ing the healing they are constantly soaked in 



82 FISTULA AND POLL-EVIL 

pus. Necrotic ends sooner or later, without in- 
terference, separate from the viable bone, and 
then leave it carpeted with granulations which 
now cicatrize with the rest of the wound. We 
are, therefore, unequivocally opposed to the 
removal of bone tissue other than the already 
welHoosened sequestra, which are sometimes 
found floating in the cavity or feebly attached 
in situ. 

The fourth step is the insertion of the drain- 
age tube. This is done with the drainage tube 
inserter. (Fig. 3.) 

Armed with the tube the point of the inserter 
is placed at the bottom of the cavity and then 
pushed out laterally in the downward direction 
through the splenitis and serratus cervicis mus- 
cles to the surface. The skin must be incised 
as the point of the inserter bulges it out as its 
point is not sharp enough to penetrate it un- 
assisted by an incision. When inserted on the 
one side the inserter is passed into the other 
end of the tube and pushed through the same 
place on the opposite side. This places the 
tube across the bottom of the cavity and out to 
each side of the neck. (Fig. 4.) 

When the operation is prolonged for any 
cause and the blood loss has been great, we 
postpone the insertion of the tube until the 



TREATMENT 83 

second dav, at which time it is inserted in the 
standing position. 

It is advisable in passing tubes through this 
thick musculature to keep the neck in a nor- 




Fig. 7.— Inserting the Drainage Tube. 

mal position. Otherwise the tube will be in a 
strained position. 

The fifth step is that of packing and sutur- 
ing the cavity. For this we use sterilized anti- 
septic oakum. We prepare the oakum already 



84 



FISTULA AND POLL-EVIL 



arranged in wads of different sizes so that it 
can be packed into the recesses piece by piece 
where it will press directly upon the bleeding 
vessels and thus arrest the hemorrhage at once. 
If indifference is displayed in this connection, 
the bleeding may force its way between the 




Fig. 8. — The Drainage Tube Inserted. 
This shows the position of the drainage tube in an atypical 
case of fistula before the would is sutured. In typical fistula 
the tube would be inserted more anterior, making its exit at 
the point marked X. 

layers of the surrounding tissues. Once well 
packed the wound is closed with sutures deeply 
inserted into each lip. The wound must be 
closed tight to prevent any further blood loss. 
Dressing. When the patient rises to its feet, 
its body is washed free of all blood accumula- 



TREATMENT 



85 



tions, and rubbed as dry as possible. We then 
cover the withers with a layer of cotton or 
gauze and hold it in place with a muslin or bur- 
lap sheet tied down with cords encircling the 
breast and the girth. The patient is now ready 
for the stall. 

After-care. At the end of twenty-four hours 




FiG. 9. — The Drainage Tube After the Wound Has Been 
Sutured, Typical Fistula. 

the sutures are removed and the packing lifted 
out carefully. There is at this time still some 
danger of bleeding if the interior of the cavity 
is harshly handled. We, therefore, advise that 
no attempt be made to clean out the blood clots 
attached here and there about the cavity until 
the end of forty-eight hours, but that we con- 
tent ourselves with a second packing of oakum 



86 



FISTULA AND POLL-EVIL 



or gauze soaked in mercuric chlorid solution 
and bound down with the withers bandage. At 
the end of forty-eight hours we give the whole 
cavity a good cleaning under strict aseptic pre- 
cautions, removing the blood clots attached to 
the tissue completely. The cavity is now 
sprinkled with iodoform and then filled up with 




Fig. 10. — The Drainage Tube After the Wound Has Bern- 
Sutured, Atypical Fistula. 

a mixture consisting of iodoform five per cent 
and boric acid ninety-five per cent and the 
withers protected again with clean cotton and 
the bandage. 

In cases where the wound has not been soiled 
during the operation a daily renewal of the 
antiseptic powder after wiping out the old will 



TREATMENT 87 

answer for the after-care, but where the cavity 
was found badly infected or in instances where 
the operation was not a perfectly clean one, it 
is essential that the powder be renewed no less 
frequently than three times a day for the first 
four days. By attending with great care to 
this large wound, the discharges will not be 
abundant, but when the whole area of exposed 
flesh is allowed to become contaminated the is- 
sue is copious. It is, therefore, important to 
pay strict attention to the wound, treating it 
skillfully during the first four days. After 
four days there is less danger of grave infec- 
tions gaining any headway in the wound as 
the tissues are then better protected against 
microbian invasion. 

The drainage tube is managed much like a 
seton. We fasten a spike across one end and 
then pull it through from the other end and 
give the holes and lumen a good cleaning. A 
stylet is needed to dislodge the dried pus that 
chokes it. By bending it about, cleaning its 
holes and ramming a stylet through its lumen 
and then rinsing it well with a strong antisep- 
tic solution, it can be kept perfectly clean and 
open. The next day the same manner of hand- 
ling is repeated except that it is drawn to the 
opposite side. 

Cases having an osseous complication should 



88 FISTULA AND POLL-EVIL 

be watched more carefully. They must not be 
allowed to close above before sequestration is 
complete and the bone is in condition to cica- 
trize with the rest of the wound. It is here 
that recurrences occur. Stumps of bare verte- 
brae are covered by scar tissue and cause a re- 
accumulation of pus which will require subse- 
quent attention if not a second operation of 
equal magnitude. 

During the healing of the wound its walls 
are scrutinized daily for shreds of ligament 
that are becoming surrounded with granula- 
tions before detaching from their viable con- 
tinuation. It often happens that large sloughs 
of ligamentous or new-formed fibrous tissue 
appear here and there about the cavity as cica- 
trization proceeds. These delay healing and 
should be removed as soon as possible. 

At the end of five weeks we usually dispense 
with the tube and apply such simple astring- 
ents as a two per cent solution of zinc sul- 
phate or common white lotion. At this time 
horses may be worked with breast harness 
but collar pressure directly upon the region is 
not admissible until after three months have 
elapsed. 

Modifications 

Large subcutaneous or subfascial abscesses 
are evacuated at dependent points and drain- 



TREATMENT 89 

age apertures maintained as long as there is 
any issue from them. When the discharge 
continues to be profuse, attempt should be 
made to locate the cause. The main cavity has 
not been drained. If located in an inaccessible 
place, as for example upon the cervical verte- 
brae (cervical fistula) or along the thoracic 
vertebra? under the longissimus dorsi, spinalis 
or complexus, it may not be possible to give 
helpful assistance. These secondary abscesses 
are the result of improper treatment or neglect. 
They seldom if ever complicate a well directed 
operation followed by faithful after-care. 

In the case of atypical fistula arising from 
wounds of the back or crest, the operation is 
much the same except that the incision is made 
more posteriorly (Fig. 10). 

It is, however, never advisable to make such 
a median line incision on a thin horse having a 
prominent, sharp withers, as the wound lips 
will sag down below the level of the vertebrae 
and produce a condition that will heal very 
slowly and imperfectly. In draft horses with 
thick, low withers there is less danger from this 
standpoint. The fleshy surrounding affords 
ample protection against protrusion of the 
crest above the level of the wound edges. 



90 FISTULA AND POLL-EVIL 

Special Remarks 

Objections have been raised against the use 
of drainage tubes in the treatment of fistula 
on the grounds that they are difficult to keep 
open. This objection we are sure comes from 
those who have not persevered in their use. A 
tube long enough to cross the neck and pro- 
trude no less than eight inches on each side is 
very easily cleaned without removing it en- 
tirely, as described above, and after it has es- 
tablished a good tract for itself it can be taken 
out entirety for cleaning and can be easily rein- 
serted. It is essential that a tube be composed 
of strong material, strong enough to resist the 
pressure upon it. It must not collapse. A 
soft tube is worthless. When the strong mus- 
cles through which it passes press upon it, its 
usefulness for drainage is destroyed. We, 
therefore, recommend a stong reinforced rub- 
ber hose which we perforate with a harness 
punch (Fig. 6.) 

To prevent drainage tubes from coming out 
we arm each end with a common twenty penny 
nail passed across at right angles. A meat 
skewer or common round stick will also answer 
the same purpose. 

It seems important to emphasize here the 
worthlessness of mere incisions through thick 
muscles as drainage apertures. A collapsed 



TREATMENT 91 

aperture through muscle tissue does not drain 
in the surgical sense. Such an aperture leaks 
pus but does not drain the cavity dry enough 
to serve the purpose for which drainage is 
needed. It does not matter how many drain- 
age incisions are made through muscle tissue, 
the cavitv would still overflow unless the aper- 
tures are held wide open with a tube. The 
same may be said of setons. While pus is ab- 
sorbed by them (in very limited quantities) 
they do not empty the cavity and are, there- 
fore, worthless. To heal a wound as large as 
the one required to expose the diseased part of 
a fistula of the withers, it is essential that it be 
kept free from accumulations of its secretions. 

Accidents and Sequelae 

Septicemia is the commonest sequel of the 
operation. It is predisposed by enfeebled 
states of the patients but can often be traced 
to badly directed surgical work. Failure to 
obey the common laws of modern surgery as 
regards asepsis is always disastrous in opera- 
tions of this magnitude, and since this one is 
performed often in a pus ridden region, dirty 
internally and externally, and must often be 
done where conditions are none too favorable, 
the operation exacts its full toll of fatality 



92 FISTULA AND POLL-EVIL 

from septicemia, even in the most vigorous sub- 
jects. 

The prevention lies in making the best of 
the situation by using sterilized instruments, 
cleaning the hands well, packing the wound 
with a safe wadding and then protecting it 
thereafter until the danger of a grave infection 
has passed. It is also very essential to remove 
the packing material at the end of twenty- four 
hours so that the blood supply of the tissues 
pressed upon by the tight packing will be re- 
stored to the walls of the wound. A packing 
of doubtful purity wadded tightly into a 
wound as large as this one is indeed a hazard. 
It weakens the tissues and besides impregnates 
them with infections. 

Malignant Edema 

We have had cases of malignant edema fol- 
low operations where the directions given about 
the removal of the packing were not carried 
out. To let a packing sojourn forty-eight 
hours in a large wound always invites anaer- 
obic infections of this character. In fistulas of 
the withers it is positively disastrous. There 
is danger from this disease even after appar- 
ently clean operations because the condition 
created is so favorable. The prompt removal 
of the packing at the end of twenty-four hours 



TREATMENT 93 

and the re-application of a well soaked anti- 
septic pack is universally preventive. 

Hemorrhage 

The blood loss, always considerable, often 
reaches the danger point when large radicals 
of the nutrient arteries are divided and the clos- 
ing up of the wound is in some way delayed. 
We depend more upon hasty work and prompt 
closure of the cavity to limit the blood loss 
than upon ligation or forcep hemostasia. Often 
when blood is gushing from some part of the 
wound in a threatening manner and a forcep 
cannot be snapped upon it promptly we pack 
the bleeding place with a hard wad of oakum 
and let an assistant hold it down tight with a 
long blunt instrument while the work proceeds 
without further hindrance. While cognizant 
of the fact that this is not a display of the best 
surgery, it has always seemed impossible for 
us to make any headway in the direction of sys- 
tematic hemostasia in these operations and we 
have come to the conclusion that less blood is 
lost by hurrying through the work and then 
depending upon the packing to prevent any 
further loss. 

In exceptionally large withers, infiltrated 
with an abundance of newly formed fibrous tis- 
sue, the wound is of such magnitude that in 



94 FISTULA AND POLL-EVIL 

spite of care the loss of blood assumes danger- 
ous proportions. And while fatalities from 
this cause are not usual, the weakened state 
produced by excessive bleeding operates with 
other influences against the general welfare of 
the patient during the first few days of con- 
valescence. 

Recurrence 

When the withers tumefy again after the 
wound has been healed for some time or when 
it does not heal in the usual time, it is evident 
that some necrotic ligament or bone still re- 
mains. These may have been overlooked in the 
operation or else the disease may have ad- 
vanced into adjacent places. We have found 
that most of our recurrences are due to healing 
of the wound before the spines have cast off the 
sequestra. A second operation of lesser mag- 
nitude often reveals a loosened segment which 
on removal is followed by prompt cicatrization. 
When this is not found to be the cause a new 
operation the same as the first may be required. 

Complications 

The complications arising from fistula of the 
withers independent of those caused entirely 
by operations and other remedial measures 
which will be considered under the head of "se- 



TREATMENT 95 

quels and accident" are: Acute septicemia, 
chronic septicemia, pneumonia, pleurisy and 
paralysis. 

1. Septicemia. As already mentioned under 
the chapter on pathogenesis, there is a toxemia 
associated with every case of fistula. The only 
exception is during the saccular stage of the 
typical form. After infection has entered, the 
situation is only a question of how badly the 
patient is affected by this complication. Some 
patients resist this systemic complication bet- 
ter than others, but after a fistula has become 
chronic and has drained the patient's vitality 
by copious discharges of pus for a long while, 
impregation of the organism^ with toxic prod- 
ucts and bacteria occurs to a greater or less 
extent in every case. Death from acute sep- 
ticemia, except after operations, is rare, but 
clinical chronic septicemia is a very common 
occurrence. It is this complication that most 
undermines the health of all cases and which 
causes the emaciation and general enfeeble- 
ment alreadv referred to. And while the com- 
plication is an insidious one, deaths occur 
therefrom quite often. We have found sec- 
ondary abscess of the lungs and of the spleen 
in animals that have died from fistula. As a 
source of focal infection fistula? of the with- 



96 FISTULA AND POLL-EVIL 

ers is by far the best example we have in 
domestic animal pathology. Its symptoms are 
seen in the unthrifty and enfeebled state of 
the patient and in its susceptibility to other 
diseases, particularly to new infections after 




Rig. 11.— A Complicated Case of Fistula and Poll-Evil. 

operations, and to pneumonia — the common 
form of dissolution of so many diseases. 

Pneumonia 

The pneumonia arising as a complication of 
fistula of the withers occurs chiefly in old debil- 
itated subjects or in younger animals reduced 
to a state of general enf eeblement from neglect 
and exposure. It is sometimes also metastatic- 
abscess of the lungs — the infection is carried 
from the purulent hot bed to the pulmonary 



TREATMENT 97 

capillaries where the lung tissue falls an easy 
prey to the subsequent pyogenesis. We have 
found the lungs riddled with abscesses in af- 
fected horses that have died from fistula. 

Pleurisy 

The pleura is occasionally attacked with an 
inflammatory process arising from its conti- 
nuity with the affected musculature surround- 
ing it. The deep secondary abscesses which 
burrow down to the bodies of the vertebras and 
then descend over the costal surface are the in- 
fluential factors in this connection. At first cir- 
cumscribed, the inflammation soon extends over 
a wider surface until the subject is affected with 
a diffuse fatal sero-fibrinous pleuritis. Figure 
1 1 illustrates a case affected both with poll-evil 
and fistula? of the withers. The subject was 
seven years and a fair type of delivery wagon 
horse weighing eleven hundred and fifty 
pounds. It was first attacked with poll-evil, 
but before this was submitted for treatment 
the withers were already tumefied with a 
phlegmonous enlargement. The poll-evil was 
submitted to the radical operation and 
promptly cured after thirty days. During this 
period of convalescence from the poll-evil oper- 
ation, the withers pointed and discharged a 
copious quantity of pus on the right side ad- 



98 FISTULA AND POLL-EVIL 

jacent to the cervical angle of the scapula. The 
patient was not relieved from this evacuation 
but on the contrary remained indisposed, re- 
fusing to move about except when urged, and 
at each movement grunted with agony. The 
respirations at first only slightly accelerated 
became gradually faster during the succeeding 
three weeks, at which time several gallons of 
exudate were aspirated from the right side of 
the thorax. The patient's condition became 
gradually worse and at six weeks following the 
evacuation of the withers it died from a re- 
filling of the pleural sacs. The post mortem 
examination of the carcass showed clearly a 
case of pleurisy beginning along the dorsal re- 
gion extending with a gradual lessening in- 
tensity in the downward direction over the 
thoracic parietes, beginning at the intercostal 
lymph nodes, which were found enlarged. 

Paralysis 

Nervous involvement is less likely to com- 
plicate fistula of the withers than poll -evil, be- 
cause the spinal cord of the dorsal region is 
better protected against encroachment from 
extending pyogenic processes. We have never- 
theless observed cases in which death due to 
spiivkis arising from extension of the 
disease into the neural canal. The patients al- 



TREATMENT 



99 



readv weakened from the disease and also from 
general neglect weakened in the hind quarters 
and after exhibiting a progressive paralytic 
state, were finally found unable to rise, dying 
in delirium after some days of decumbency. 




Fig. 12. — Cold Abscess of the Prescapular Lymph Nodes. 
Following Fistula of the Withers. 

Cold Abscess of the Prescapular Lymph Nodes 

The adjacent lymph nodes may suppurate 
during or following fistula of the withers as 
shown in case of a draft horse (Fig. 14) . After 
recovering from an operation for a fistula of 
the withers and before having been put to 
work a pronounced enlargement developed at 



100 FISTULA AND POLL-EVIL 

the shoulder. This proved to be a typical cold 
abscess involving these lymph nodes. 

Fistula Caused From Collar Sitfasts 

There is a type of fistula that differs some- 
what from those just described. It is located 
in front of the generally accepted limits of the 
withers proper, and it exhibits certain etiologic, 
pathologic and clinical differences that call foi 
a special description and which require differ 
ent methods of management. 

This injury starts as a cutaneous collar le- 
sion. It begins as a pressure necrosis of the 
skin alone but later involves first the pad of the 
mane and then the funicular portion of the 
ligamentum nucha? and even extends down- 
ward into the lamellar portion, creating a very 
troublesome condition to treat. 

When observed in the early stage of devel 
opment, the seat of the collar at the level of 
the mane where the thick skin is folded trans- 
versely into several deep undulations, is found 
to contain a black, smooth, hairless, leather- 
like, circular zone of insensitive integument 
that is loosened slightly from the viable skin 
all around its circumference, but which can not 
be lifted off. It is attached and although some 
time is given for it to separate, no such an event 
occurs. It remains stubbornly attached. At 



TREATMENT 101 

first there is no swelling and the patient dis- 
plays little discomfort, but later when the dead 
tissues begin to putrefy and impregnate the 
adjacent tissues with infections or serve as an 
avenue of entrance into them, the subject be- 
comes unfit to work with a collar, a certain 
amount of discharge begins to appear around 
its borders, and the subjacent musculature be- 
comes swollen or bulges from the swollen lig- 
aments within. Soon the slough which is a large 
cone-shaped mass of skin and pad detaches 
itself and can then be removed by blunt dis- 
section, leaving a deep well whose bottom is 
the ligamentum nuchse. Treated as an open 
wound the cavity often closes up with nothing- 
more harmful than a slight deformity of the 
neck which will vary according to the size of 
the slough removed. 

Many cases, however, do not behave so well. 
Cicatrization of the cavity leaves a small fistu- 
lous tract that runs down to and often under 
the ligamentum nucha?, and which in spite of 
local treatment continues to discharge consid- 
erable pus. The sides of the neck along the 
ligament bulge slightly in both the forward and 
the downward directions. This is fistula from 
sitfast. Later if no relief is given the lamellar 
portion becomes involved, at first only slightly 
but later over a wider and wider zone until the 



102 FISTULA AND POLL-EVIL 

whole lower third of the cervical region is hard 
and tumefied. Abscesses may point well for- 
ward along the neck and as far down as the 
level of the vertebrae. This is cervical fistula, 
a type that may also result from either the typ- 
ical or the atypical types previously described. 
The treatment of fistula from sitfast should 
begin with prevention. That is to say, the sit- 
fast should be properly managed. It is an 
error to allow even the smallest superficial 
sitfast to sojourn on the neck unchecked. The 
veterinarian should recommend prompt extir- 
pation and give warning about the serious state 
that may develop from careless treatment 
thereafter. The sitfast should be extirpated 
down into the sound, unaffected tissues, no 
matter how far it may extend, and the subject 
must be removed from service or worked with 
a breast collar. To leave any part of the dead 
tissue in the cavity or to subject the neck to 
continued injury by working the patient with 
a collar will encourage the development of 
chronic fistula and the attendant results. We 
therefore advise that all sitfasts be managed 
with this end in view, that the patient be sub- 
mitted to a proper operation and the wound 
treated as it should be after the operation. The 
extirpation of deep sitfasts and the application 
of caustic into the cavity in our hands have not 



TREATMENT 103 

been found to be good practice. We have de- 
pended upon the completeness of the extirpa- 
tion as the main treatment, and in order to 
properly carry out this plan we have found 
it necessary to place the patients in the re- 
cumbent position with the neck well stretched 
downward to expose the field to the best ad- 
vantage. Attempts to extirpate sitfasts of 
this character in the standing position end in 
failure to remove all of the dead elements. 
With the head elevated, the skin folded, the 
patient lunging about and the blood masking 
the view, it is never possible to work accu- 
rately, and a misdirected or incomplete extir- 
pation is the result. 

By placing the patient on the operating table 
or down on the ground with ropes, the neck 
can be drawn downward, the parts cleaned, 
the blood well baled and the whole mass of 
dead and unviable tissues can be cut away. 
Prompt healing will then follow. 

Once the fistula has formed it will be neces- 
sary to operate promptly to prevent the spread 
of the advancing inflammation into the lamel- 
lar portion of the ligament. 

We cast the patient clean and shave the neck 
and then make an incision no less than eight 
inches long in the median line through the 
skin, pad of the mane and down between the 



104 FISTULA AND POLL-EVIL 

two halves of the ligament. Widening the 
wound with the tumor forceps we then resect 
as much of the ligament as is thought to be 
diseased, making sure that the lowest limits of 
the disease have been reached. In the average 
case, not yet encroaching into the lamellar por- 
tion, the bottom of the cavity is found just 
under the funicular portion of the ligamnt. 
The wound is treated without drainage by 
smothering it well with boric acid and iodoform 
until cicatrization is well advanced. 



POLL-EVIL 

The Poll 

The poll or nape of the neck of quadrupeds 
having a long highly mobile neck and large 
head is an important region. Although less 
complicated from the anatomical standpoint 
than the withers it is nevertheless composed of 
a great many separate anatomical structures 
and although more shallow than the withers 
its relations to the large nerve centers makes 
affections of the poll more or less dreaded from 
the view point of disease and of surgery. The 
structures involved in poll-evil are contiguous 
to the coverings of the spinal cord in the 
atlanto-axoid space, to the occipito-atlantoid 
articulation and finally to the meminges and 
the brain. It is plain that no chronic patholog- 
ical process so serious as poll-evil can so- 
journ unchecked without sooner or later im- 
plicating some of these structures if not all of 
them. The surgical anatomy of the withers 
does not include a trochoid articulation and its 
relations to the spinal cord are more remote. 

The surgical anatomy of the poll includes, 
the skin, the pad of the mane, the atlas, the 



106 FISTULA AND POLL-EVIL 

axis, the occipital crest, the occipito-atlantoid 
articulation the atlanto-axoid ligament, the 
spinal cord, the funicular portion of the liga- 
mentum nucha?, the musculature, the blood sup- 
ply, the anterior end of the spinal cord the 
meninges, the medulla oblongata, the spinal ac- 
cessory nerve, and the first two spinal nerves. 

The skin of the central line of the poll is 
thick and insejDarable from the thick pad of the 
mane lying immediately beneath it. On the 
sides of the mane it is thin, somewhat delicate 
in texture, but possesses nothing out of the 
ordinary to describe. On the sides, the borders 
of the wing of the axis can be felt through it. 
Elsewhere the outlines of the bones can be 
palpated through it. In old cases of poll-evil 
it is riddled with perforations and often it con- 
tains scars of previous perforations. 

The pad of the mane at the poll is very 
heavy especially in the draft breeds of horses, 
often exceeding two inches in thickness. In the 
lighter breeds as for example the thorough- 
breds it is thin and in some subjects it does not 
exist. The pad here like that at the base of 
the neck is composed of elastic tissue and fat 
matted into a very firm structure homogeneous 
in appearance, and always very vascular. 

The atlas, or first cervical vertebra possesses 



POLL-EVIL 107 

none of the characteristics of vertebrae in gen- 
eral. It articulates by means of diarthrodial 
articulations with the occipital condyles an- 
teriorly and with the odontoid process of the 
axis posteriorly. Its wide expansive dorsal 
surface gives attachment to the muscles to 
which it is related. 

Its wings which extend downward and out- 
ward become gradually thinner and thicken 
again into a roughed heavy border. Each one 
is perforated with a large foramen which gives 
passage to the occipital artery, in its course 
from the carotid to the region of the poll. 

The whole dorsal face is a smooth expanse 
interrupted only by a slight median elevation 
representing the superior spinous process. 

The dorsal surface of the atlas is important 
in poll-evil because it sooner or later becomes 
affected with periosteitis and osteitis on ac- 
count of its close relations to the disease process 
in and about the ligamentum nuchae. It 
serves as a floor for the abscess cavity from 
which it is often separated only by a carpet of 
granulation tissue attached to the periosteum. 
The axis or second cervical vertebra may be 
said to be the posterior boundary of the poll- 
evil process. It is seldom itself involved in 
disease. Its crest or superior spinous process 
stands above the level of the axis where it serves 



108 FISTULA AND POLL-EVIL 

as a pillar for the ligamentum nuchas to bridge 
over the space between it and the nuchal (oc- 
cipital) crest. The ligamentum nuchas is, how- 
ever, attached to it only by the lamellar por- 
tion, which at this point is very thick. 

The nuchal (occijntal) crest is a process of 
the occipital bone extending upward to give 
attachment to the ligamentum nuchas and to 
the muscles of the poll. It has a rough border 
and a somewhat concave posterior face which 
is depressed at one point on each side of the 
median line to receive each half of the ligament. 
Its upper outlines determine the profile of the 
space between the ears. 

The compact tissue of the occipital crest is 
dense and hard particularly along the summit. 
The cells of the cancellated tissue are large and 
the plates separating them are thin and there- 
fore easily permeated with inflammatory proc- 
esses. Although the occipital crest is not en- 
croached upon by disease in poll-evil itself, it 
sometimes becomes affected by a chronic os- 
teitis from chiseling into it to effect drainage 
as recommended by Williams. 

The atlanto-aocoid ligament covers the gap 
intervening dorsally between the anterior por- 
tions of the axis and the posterior part of the 
atlas. This space is about an inch and a half 
to two inches long and about an inch wide, be- 



POLL-EVIL 109 

neath which lies the spinal cord unprotected 
by bony covering. Above the intervertebral 
ligament there is a thick musculature and the 
funicular portion of the ligamentum nuchas. 

The occipito-atlantoid articulation is a diar- 
throsis whose large capsular ligament is ar- 
ranged to include both occipital condyles. It 
is protected superiorly by muscles which also 
separate it from the ligament laterally. 

The atlantoid bursa — the initial seat of al- 
most all poll-evils — lies between the ligamen- 
tum nuchas and the dorsal arch of the atlas. 
This bursa has no connection with the articu- 
lation. 

The spinal cord is exposed in two places to 
both the disease and the operation against poll- 
evil. It is, however, in the atlanto-axoid space 
that it is most likely to be encroached upon. 
The musculature covering it in the atlanto- 
axoid space or the intervertebral ligament, is 
usually the floor of the abscess cavity but some- 
times these structures are degenerated and per- 
forated in a downward direction until first the 
meninges and later the cord becomes involved. 
The cord exposure in the space is about one 
and a half to two inches. The cord must also 
be thought of when packing wound cavities 
with hemostatic packs because its covering is 
compressible and considerable spinal pressure 



110 FISTULA AND POLL-EVIL 

may be caused by wadding the cavity too tight. 

The other place through which the spinal 
cord becomes exposed is at the occipito-atlant- 
oid articulation. Here it is attacked by en- 
croaching disease after the capsule of the joint 
has been invaded. 

The ligamentmn nuchae is a powerful, elas- 
tic apparatus, the principal function of which 
is to assist the extensor muscles of the head and 
neck. It extends from the occipital bone to 
the withers, where it is directly continuous with 
the supraspinous ligament. It consists of two 
parts, funicular and lamellar. 

The funicular part arises from the external 
occipital protuberance and the fossa below it 
and is inserted into the summits of the verte- 
bral spines at the withers. — Sisson. 

It is between the funicular portion of this 
ligament and the dorsal arch of the atlas that 
the bursa (supra-atloid) lies. At the pole the 
funicular part consists of two bands closely at- 
tached to each other. The lamellar portion of 
the ligamentum nuchae is not attached to the 
atlas, but begins at the axis to which a very 
thick and strong digitation is attached. 

Obliquus Capitis Anterior. This is a short, 
flat and nearly square muscle, having tendin- 
ous intersections. It originates from the an- 
terior edge and, ventral surface of the wing of 



POLL-EVIL 111 

the atlas inserts to the parmastoid process 
nuchal (occipital) crest and the mastoid pro- 
cess. 

Obliquus Capitis Posterior (Posticus) . This 
muscle lies upon the dorsolateral aspect of the 
atlas and axis. It is broad, flat, thick and 
fleshy. Its origin is from the side of the spine 
and the posterior articular process of the axis. 
It inserts to the dorsal surface of the wing of 
the atlas. Its function is chiefly to rotate the 
atlas, and by this means, the head. 

Rectus Capitis Dorsalis Major. This mus- 
cle originates from the edge of the spinous 
process of the axis and inserts to the occipital 
bone, below the tendon of insertion of the corn- 
plexus. It is in contact with the ligamentum 
nucha?. 

Rectus Capitis Dorsalis Minor. This is 2 
small muscle which lies under the rectus cap- 
itis dorsalis major. It originates from the 
dorsal surface of the atlas and inserts to the 
occipital bone beneath the point of insertion of 
the last named muscle. It is lateral to the 
cordiform portion of the ligamentum nucha?. 

Rectus Capitus Ventralis (Anticus) Major. 
This, the long flexor muscle of the head has its 
origin posteriorly from the transverse process- 
es of the third, fourth and fifth cervical verte- 



112 FISTULA AND POLL-EVIL 

brae. It inserts to tubercles which occur at 
the junction of the basilar part of the occipital 
bone with the body of the sphenoid. These 
muscles (the pair) may be said to form a roof 
for a part of the pharynx. 

The blood supply of the poll is from three 
sources: The occipital, the superior cervical 
and the vertebral arteries. The first named 
is, however, the chief one. It is a radical of 
the carotid and passes to the region of the poll 
through the large foramen in the wing of the 
atlas. Its branches anastomose with the other 
two. The branches are numerous and often 
through the influence of the disease become 
greatly enlarged. In the operation for poll- 
evil the incision being a standard one, made 
irrespective of blood vessels, there is nothing of 
importance to say about avoiding them, ex- 
cept that lateral invasion into the region of the 
alar foramen through which the occipital passes 
must be made cautiously. In short, no especial 
effort except this one, is ever made to avoid 
arteries. 

The nerve sup ply is of no especial impor- 
tance. It is derived from the spinal accessory 
and the first two spinal nerves, none of which 
is ever seen in the operation, nor is a solution 
on the continuity of their branches attended 
with any observable harm. 



PATHOGENESIS 

Poll-evil, like fistula of the withers, we di- 
vide into two classes : typical and atypical. By 
typical poll-evil we mean those cases that de- 
velop independent of any known cause in the 
atlantoid bursa, just as fistula of the withers so 
frequently develops in the dorsal bursa. By 
atypical poll-evil — a rare entity — we designate 
those that originate from abrasions or wounds. 
The former invade outward while the latter in- 
vade inward from the initial seat. 

The course of all typical p c oll-evil we divide 
into three stages : the saccular stage, the phleg- 
monous stage and the fistulous stage, as in fis- 
tula of the withers. 

The saccular stage begins in the form of a 
distension of the atlantoid bursa with a sero- 
fibrinous fluid that is sterile and whose influ- 
ence causes the formation of a well defined 
membranous wall composed of a cellular inter- 
nal face fortified by fibrous tissue. As the les- 
ion becomes older the fibrous tissue becomes 
more abundant, sometimes amounting to an 
extensive fibrosis of the surrounding muscula- 
ture. The sac may bulge on one or both sides 
and may be small or large enough to conspicu- 



114 FISTULA AND POLL-EVIL 

ously deform the region. Being imbedded un- 
der firm tissues, it is often hard to the touch, 
fluctuating only after pushing its way to the 
surface on the side of the ligamentum nuchae 
and pad of the mane. Evacuating the contents 
of the sac during this stage yields an amber 
colored fluid carrying coagulated detritus con- 
taining no bacteria. 

This sac may sojourn indefinitely and may 
even for a time seem to disappear entirely, only 
to reappear subsequently. 

Evacuation and careful attention to the 
tract and cavity may sometimes end the pro- 
cess by slow cicatrization. Thus sometimes a 
poll-evil is cured without a radical operation. 
In most cases, however, the invasion of the 
tract and cavity with extraneous microbes 
ends in chronic fistula. 

The phlegmonous stage. In the usual course 
of events the saccular stage ends in infection of 
the cavity. The manner in which microorgan- 
ism gains access to the cavity is not known, 
but the frequency with which poll-evil is asso- 
ciated with strangles and influenza has led us 
to believe that these diseases play an important 
role in its etiology ; the affected atlantoid bursa 
serving as a focus of localization for microor- 
ganisms contained in the blood after these dis- 
eases. 



PATHOGENESIS 115 

During this stage the patient becomes sick 
and severely hindered in the movements of the 
head. It becomes manifestly opisthotonic in 
attitude, and develops a body temperature of 
from two to three degrees above normal. The 
poll becomes progressively more painful to the 
touch and the sides of the neck are streaked 
with radiating lines. 

The Fistulous Stage 

Either by lancing or by spontaneous ripping 
and bursting of the abscess this stage sooner or 
later passes into the stage of chronic discharge 
— fistula. If the infection is not a virulent one 
the development is very slow — cold abscess— 
and fibrosis becomes a prominent feature of the 
process. That is to say, if the accumulating 
pus is not released the process reacts upon the 
surroundings in some way that causes the mus- 
cular elements to become fibrous. 

The fistulous and the phelgmonous stages 
are of course influenced by microorganism. 
These exert a more or less destructive influence 
upon the ligamentum nuchas, which is in the 
center of the theater of attack. Once this fibro- 
elastic structure has been damaged it acts as 
the underlying cause of subsequent pathologic 
processes. Riddled with perforations, shred- 
ded with bundles of its fibers which remain 



116 FISTULA AND POLL-EVIL 

stubbornly attached, and carpeted here and 
there with dormant granulations it prevents 
cicatrization of the abscess cavity. It is this 
stubborn viability of the ligamentum nucha? 
that is responsible for the chronicity of poll- 
evil. 

This stage, like that of fistula of the with- 
ers, continues indefinitely, healing at one place 
and bursting at another and all of the while 
transforming the muscles into fibrous tissue. 
The inflammatory process extends into the per- 
iosteum of the atlas, into the capsule of the oc- 
cipito-atlantoid articulation, into the meninges 
and brain, into the neural canal and into the 
spinal cord, producing the variety of compli- 
cations for which poll-evil is known. 

An old poll-evil left to sojourn unmolested 
or one indifferently treated usually exhibits 
the following morbid states: a tumefied poll, 
one or more apertures discharging pus, scars 
of previous apertures, encrustations of dried 
pus matted into the mane and surrounding 
hairs, extended head from fibrous anchylosis 
of the occipito-atlantoid articulation and a wab- 
bly gait that becomes more and more accentu- 
ated until the patient is unable to rise. Sec 
tioned, the poll is found to have been trans- 
formed into a mass of hard, fibrous tissue, 
which fuses all of the component structures in- 



PATHOGENESIS . 117 

to one homogenous mass. This mass is riddled 
with tracts and under the now unrecognizable 
ligamentum nuchae is an abscess cavity almost 
closed by granulation tissue. The surface of 
the atlas is rough from destruction of its peri- 
osteum and it may be studded by numerous 
vegetations of bony growths. There is found 
sometimes a shredded condition of parts of the 
ligament, parts that have partly loosened from 
necrosis. In some cases, usually in aged horses, 
the ligament is permeated with calcareous de- 
posits, each of which is well incarcerated with 
connective tissue elements. 

Atypical Poll-Evil 

The atypical poll-evil begins with a halter 
abrasion of some kind of wound that 
gives admission to pyogenic microorganisms. 
It is at first a subcutaneous abscess, 
and if carbuncular in character may give 
rise to all of the symptoms of a typical 
poll-evil in the phlegmonous stage. This 
form will differ from the typical form in 
that cicatrization will follow evacuation of its 
pus and general slough. If deep and the 
slough should be attached to the ligamentum 
nuchse a chronic poll-evil having all of the char- 
acteristics of the other, the typical kind, will 
supervene. In this case the ligament is at- 



118 FISTULA AND POLL-EVIL 

tacked from without. Its dorsal face is at- 
tack first, while in the other, the under part 
at the atlantal bursa, is attacked before the 
upper part becomes involved. 

This form of fistula can only be recognized 
as such at the early stage, for once spread 
deeply into the poll it has no differentiating 

qualities. 

Etiology 

The cause of poll-evil, like that of fistula of 
the withers, is by no means settled. The aca- 
demic explanation ( traumatism ) that seems to 
have satisfied all past writers on the subject 
entirely lacks confirmation. Wherever this 
subject is discussed verbally or in literature the 
matter of etiology is always indifferently 
passed over as if it is a settled fact that poll- 
evil is a traumatism. No one seems to have 
ever questioned seriously the theory of trau- 
matic origin in spite of the fact that no one 
seems to have ever actually traced a typical 
poll-evil to any definite traumatism. The 
truth seems to be that traumatism plays no 
part whatever in its cause. Except in the rare 
case that originates with a wound of the poll 
it is plain that we must seek farther for a rea- 
sonable theory of cause. It is our opinion that 
the cause is unknown, that the serous sac that 
starts it develops under influences we cannot 



PATHOGENESIS 119 

explain at the present time. We believe, how- 
ever, that infectious diseases such as influenza 
or strangles play an important role in the 
course if not also in the original cause. Where 
influenza is rampant so will poll-evil and fis- 
tula of the withers be found rampant. We are, 
however, not today justified as laying this 
down as an absolute law, as subsequent inves- 
tigations no doubt may show that its cause 
is more specific. 



SYMPTOMS 

Typical poll-evil is first seen as a slight bulg- 
ing of one or both sides of the poll. There are 
at first no manifestations of pain either on pal- 
pation or in movements of the head. Later as 
the phlegmonous stage begins the movements 
of the head become painful and palpations an- 
noy the patient. Some will oppose any at- 
tempt to touch the region. Before the abscess 
points there are radiating lines along the sides 
of the neck. The head is held extended, later- 
al movements are painful and the whole body 
is turned stiffly, as if the whole axial skeleton 
were anchylosed. 

Later the abscess points and discharges its 
contents over the sides of the neck. The aper- 
ture may then discharge a limited quantity of 
pus for weeks that keeps the region continual- 
ly soiled and irritated. The aperture will fin- 
ally close gradually as the discharges become 
less abundant, but this will eventually be fol- 
lowed by the forming of another abscess, which 
will behave in the same manner as the preced- 
ing one, and so the condition proceeds. While 
these abscesses and tracts are forming, the mus- 
culature involved becomes considerably elevat- 



122 FISTULA AND POLL-EVIL 

ed above the surrounding level. The head, at 
first extended from the pain of the forming ab- 
scesses, gradually becomes fixed in the extend- 
ed position from fibrous anchylosis of the re- 
gion. An animal affected with poll-evil has a 
characteristic attitude simulating the opisthot- 
onos of tetanus. 

Poll-evil that becomes infected before there 
is any enlargement of the region must be diag- 
nosed sometimes entirely from this attitude 
and from the pain produced by manipulating 
the head. 

Rare cases cause epiliptiform seizures when 
the head is moved about manually or in work- 
ing. In such instances when local evidence is 
entirely lacking because of the depth of the 
infected focus it may not be an easy matter to 
arrive at a diagnosis. 

The development of poll-evil is always grad- 
ual, although it may often assume considerable 
proportions before attracting attention. The 
mane and forelock shelter the region so effec- 
tually in some animals that the enlargement 
develops unnoticed until discharges appear. 
These cases are, however, rare, as the pain and 
the position of the head which precede the dis- 
charge are usually pronounced enough to at- 
tract attention. 

The average poll-evil when submitted to the 



SYMPTOMS 123 

veterinarian is either found as an enlargement 
on one or both sides of the poll or else as a sup- 
purative condition that matts the hairs of the 
mane and soils the region with dried pus. 

As the disease progresses the patient be- 
comes distinctly unthrifty in appearance and 
loses flesh. Locomotion is slow. The patient 
gropes about and trots only when urged. Feed- 
ing from the bottom of the manger and grazing 
is painful. 

Later, as nervous complications develop, the 
hind quarters wabble inordinately and rising 
becomes more and more difficult. Finally the 
failing subject, unable to stand, dies from de- 
cubital complications, if it is not sooner killed 
to end its misery. 

Complications 

Paralysis. — The most serious complication 
is paralysis due to advancement of the inflam- 
matory process into the meninges, the cord and 
even the brain itself. The invasion is usually 
at the atlanto-axoid space, but sometimes oc- 
curs through the occipito-atlantoid articulation. 
When these nervous structures become in- 
volved early in the progress of the disease, the 
case is not necessarily a hopeless one because 
of the nerve involvement, since an operation 
which evacuates the pus externally may turn 



124 FISTULA AND POLL-EVIL 

the tide of the inflammatory process towards 
resolution. On the other hand, if nervous com- 
plications develop as a phase of later stages, 
the case is always hopeless. The practitioner 
is warned against operating upon such cases, 
because the operation is always blamed for the 
unfavorable termination, and in fact rightly 
so, since the advancement of the process into 
the cord and brain is accentuated rather than 
retarded by surgical treatment at this stage of 
the development. And besides, patients thus 
stricken are unable to withstand the enfeebling 
influence of such a major operation. 

Involvement of the Occipito-Atlantoid Ar- 
ticulation. — Lying adjacent to the initial focus 
of the disease, this joint very often becomes 
infected within its capsular ligament at an 
early stage. As a rule, however, this compli- 
cation features later stages, the joint becoming 
involved gradually through the medium of the 
atlas. The periosteum and then the bone, 
soaked with pus develop chronic inflammation 
that advances into the joint through the articu- 
lar cartilage. When this occurs it is only a 
matter of weeks before serious results ensue 
through involvement of the meninges. The 
subject thus affected is in sore straits from the 
severe pain it suffers, especially in moving the 
head. 



SYMPTOMS 125 

This complication is one of the common 
causes of recurrences and failures of operative 
treatment. It is incurable and if known to 
exist should be regarded as a contra-indication 
of the radical operation now universally recom- 
mended for poll-evil. 

Secondary Abscesses. — Although there are 
fewer recesses and lamellar spaces for pus to 
burrow into about the poll than there are about 
the withers, there are, nevertheless, places 
where pus will escape from the immediate re- 
gion of the seat of poll-evil and cause secondary 
abscesses. The common one that occurs both 
before and after operating, localized at some 
point of the neck along the ligamentum nucha?. 
We have observed cases in which tracts extend- 
ed down the ligament as far as the base of the 
neck, the route followed being the space be- 
tween the cervical muscles and the lamellar 
portion of the ligaments just under the fu- 
nicular portion. Most of these abscesses, how- 
ever, localize at the level of the axis, where they 
sometimes produce a stubborn condition to 
handle by implicating the lamellar portion of 
the ligament at that point. 

Another focus of abscess formation is the 
space between the anterior part of the wing 
of the atlas and the styloid process of the oc- 
cipital. This complication is disclosed at the 



126 FISTULA AND POLL-EVIL 

time of the operation. After the ligament has 
been removed, a sound can sometimes be passed 
downward five or six inches before it touches 
the bottom of the cavity. 

Chronic Septicemia co-exists to a certain ex- 
tent in all bad cases of poll-evil. It is, however, 
less serious than in fistula of the withers, since 
the region is smaller. 



TREATMENT 

No time should be lost in submitting a poll- 
evil to radical treatment. The new case 
should be lanced and the cavities irrigated 
with antiseptics for a week or ten days and 
then promptly operated upon. There will be 
nothing gained by waiting longer, as the old- 
er the case the more it will have damaged the 
structures of the region and thus the more diffi- 
cult it will be to cure. In cases found in the 
phlegmonous stage and before the abscess has 
burst we also recommend lancing and irriga- 
tions as preparatory treatment. 

Subjects having unmistakable involvement 
of the occipito-atlantoid articulation and all 
those already showing nervous complications 
should be left severely alone and pronounced 
incurable. Weak subjects that do not exhibit 
sufficient strength to withstand a major opera- 
tion should likewise be left alone. These might, 
however, be submitted to a restorative treat- 
ment until it is thought advisable to interfere 
further. 

The Radical Operation for Poll-Evil 

Restraint. — Xo attempt should ever be made 
to operate in the standing position, no matter 



128 FISTULA AND POLL-EVIL 

how tractable the patient may seem. Opera- 
tions performed in the standing position under 
some form of narcosis always turn out to be 
very unsurgical exhibitions. The patient should 
be cast with ropes or else placed upon an op- 
erating table. The latter is much the best be- 
cause of the elevated position of the head. On 
the floor or ground the field is not so accessible 
and must be elevated by blocking the neck and 
head up in some way to bring it where the sur- 
geon can Avork. Chloroformed, the patient can 
be handled better than under narcosis. When 
rope restraint is used chloroform should really 
be administered because it is difficult to control 
the sweeping movements of the head of a par- 
tially anesthetized subject down on the ground. 
Qur plan in field work is to clean up the poll 
well while the subject is standing, cast with 
ropes, administer chloroform and then block 
up the neck and poll with a tightly filled sac of 
straw. This sac may be bound to the neck and 
head with cords, one around the middle of the 
cervical region and one around the head just 
below the eyes. Thus tied the blocking will 
stay in place when the neck and head move. 
This form of blocking is particularly essential 
when the operation is done on the ground un- 
der narcosis. It is important that the sac be 
well filled, otherwise it will flatten down and do 



TREATMENT 129' 

no good. For this purpose we also use when 
available two or three buggy or automobile seat 
cushions. 

The head should be maintained at about its 
normal angle with the neck. Extreme ex- 
tension or flexion is undesirable. 

The patient should lie on its right side. Al- 
though this is not mandatory, the surgeon finds 
that it is easier to cut backward with the right 
hand when the patient is thus positioned. 

Incision. First Step. — The scalpel is pushed 
carefully downward, with its cutting surface 
backward, just behind the occipital crest in 
the very middle of the neck, until it either en- 
ters the bursa or is blocked by the occipital 
bone. Its blade should be buried about four 
inches in the average case. It is then drawn 
backward, maintaining this depth, about eight 
inches. If a longer incision is decided upon it 
is best to make it more shallow posteriorly be- 
cause of the danger of invading the neural 
canal. If a short bladed scalpel is used several 
strokes will be required. Blood will flow cop- 
iously from many sources, but no attempt is 
made to control it either by ligation or forceps. 
It is our experience that more blood is lost 
when the operation is stopped to make these 
attempts at hemostasia. We, however, grasp 



130 FISTULA AND POLL-EVIL 



each edge of the wound with a tumor forceps 
give one to the assistant and hold the other in 
the left hand. By drawing hard on these the 




Fig. 13. — Poll Evil Showing Deformity Due to the 
Treatment With Caustics. 

bleeding will be controlled to some extent. 

Separating the ligament from the occipital 

Crest. Second Step. — This to us is the most 



TREATMENT 131 

important part of the operation, as it supplies 
the first "landmark" for the subsequent resec- 
tion. Those who ignore this step will find it 




Fig. 14. — A Rkcurrent Case After Temporizing Treatment. 

Note the scars from lateral incisions through which drain- 
age had been attempted. 

difficult to locate the ligament and will often 
abandon the work without having accomplished 



132 FISTULA AND. POLL-EVIL 

the main object — the resection of the ligament. 
. In this step we lay the scalpel aside and take 
up the probe-pointed bistoury. We first pass 
the index finger of the right hand under the 
ligament right at the crest and using the finger 
as a guide pass the bistoury under it, cutting 
outward and upward. The ligament through 
its extreme elasticity will contract backwards 
as fast as it is cut and thus reveal itself to the 
operator. That is, the end will come right out 
into the foreground after contracting back- 
ward an inch or more. We then grasp the end 
with a tumor forcep and dissect it in the back- 
ward direction as it is drawn upon with the for- 
cep. Over the region most badly damaged by 
disease it will be found so fused with the other 
connective elements that it can not be said to 
be a distinct structure. We attempt to take 
away as much of this connective tissue as is 
thought prudent as the dissection proceeds 
backward. The dissection is continued along 
the whole length of the incision or until the 
sound part of the ligament is reached posteri- 
orly. We know when the sound part is reached 
by its elasticity. When the section now held in 
the forcep is drawn back and forth the liga- 
ment it seen to stretch easily. Here it is cut 
off. 

The attention is now directed to the other 



TREATMENT 



133 



side, as this removes only one-half of the liga- 
ment. The operation must be repeated in the 
same way on the opposite side. Allowance 
must be made for a possible sectioning of the 
ligament into two unequal parts when the first 




Fig. 15. — The Operation Completed. 

Note that the operative wound is packed so tightly that the 
poll appears swollen even more than before the operation. 
Note also the enlargement of the lymphatics of the neck, due 
to the absorption of toxic materials from the suppurating 
area. 



incision was made. That is to say, when the 
scalpel was drawn backward in making the in- 
cision it may not have traveled exactly be- 
tween the two lateral halves of the ligament 
and thus has left more to be removed from 



134 FISTULA AND POLL-EVIL 

one side than from the other. Sometimes in 
misdirected plunges of the scalpel into the poll 
the ligament may all be left on one side, some- 
times two-thirds is on one side and one-third 
on the other, etc. And again, if the incision 
was not made straight there may be more liga- 
ment anteriorly than posteriorly on a given 
side. These are points to keep in mind at all 
times. The point is to remove all of it along 
the affected zone, but no more than is necessary 
posteriorly. 

Packing mid Suturing. Third Step. — The 
wound is now wadded with a hemostatic pack 
of oakum and sutured securely. We make no 
attempt to wad the cavity so very tight posteri- 
orly on account of the danger of spinal pres- 
sure, although it must be well filled. The ob- 
ject in making a safe hemostatic pack for poll- 
evil is to distribute the pressure evenly over 
the whole cavity. That is, severe pressure from 
hard lumps of the oakum must be avoided, es- 
pecially at the posterior end of the wound. 
iWhen the patient is standing again the poll 
and bloody neck are washed off with liberal 
ablutions of water and then the poll is covered 
with a layer of oakum or cotton soaked in mer- 
curic chlorid solution and this is held in place 
with a hood made from muslin or common bur- 
lap. 



TREATMENT 135 

After-care. — At the end of twenty- four 
hours the sutures are removed and the packing 
carefully lifted out. Harsh handling will cause 
bleeding and should be avoided at this early 
moment after the operation. We simply fill 
the cavity with a cotton wadding dripping with 
mercuric chlorid solution and replace the hood 
for another twenty-four hours before attempt- 
ing any systemic after-treatment. 

The subsequent after-care consists of smoth- 
ering the wound secretions by the application 
of abundance of boric acid and iodoform in the 
proportion of 95 to 5. This should be applied 
three times a day for the first five days and 
later twice and still later once a day. 

Healing is usually complete in forty days. 

Accidents and Sequelae 

Hemorrhage is a common enough accident 
of poll-evil. Always copious, it assumes seri- 
ous proportions when the operation is in any 
way delayed. When the anesthesia or the 
restraint miscarries serious blood losses always 
occur. Secondary hemorrhage is rare except 
when the cavity is too hashly handled when 
the packing is first removed. 

The hemostasia of poll-evil operations lies 
in: 

1. Stretching the wound apart forcibly 



136 FISTULA AND POLL-EVIL 

with the tumor forcep as soon as the incision 
is made. 

2. Performing the operation without delay. 

3. Packing the wound with an even pres- 
sure with oakum securely retained with su- 
tures. 

4. Avoiding harsh handling until at least 
forty-eight hours have elapsed. 

Paralysis. — We have had animals become 
entirely paralyzed after poll-evil operations, 
due to having attempted to cure incurable 
cases already having nervous complications, 
but aside from those it is always possible, when 
due care is not taken to properly attend to such 
a large wound adjacent to the neural canal, 
for the inflammatory process to invade through 
the muscles covering the atlanto-axoid space 
and produce trouble that did not previously 
exist. Then again, undue pressure of a lumpy 
hemostatic pack is always a hazard. By avoid- 
ing operations on subjects exhibiting a wabbly 
gait, carefully packing the wound and then 
properly caring for it afterward there is little 
danger from this complication. 

Slough of the Distal Stump of the Liga- 
ment Nuchae. — Failure of the wound to heal 
at the posterior commissure is due always to 
a slough of the stump of the ligament. Some- 
times the slough is small and at other times it 



TREATMENT 137 

is large. This sequel is manifested in two 
ways. In some cases the wound heals every- 
where except at the posterior end, where a 
small fistulous tract remains. Probed it is 
found to be deep. If forceps are introduced 
the slough can usually be taken hold of and 
drawn out. Sometimes the aperture must first 
be enlarged. 

The other manifestation is the appearance 
of a new phlegmonous condition on each side 
of the neck just behind and below the posterior 
end of the wound. The abcess is sometimes 
threatening and unless properly handled may 
end in a new fistulous condition quite difficult 
to handle. The first sign of such a complica- 
tion, which usually occurs at about thirty-five 
to forty days after the operation, must be met 
by making an incision at the posterior end of 
the old wound downward into the abcess cav- 
ity, where a slough of the stump of the liga- 
ment is always awaiting removal. 

It is our practice to make a careful examina- 
tion of the wound at the end of thirty days 
with a view of determining whether or not such 
a slough exists, and to remove it if found. 

Recurrences and Failures 

The failures from the radical operation for 
poll-evil are almost always due to procrastina- 



138 FISTULA AND POLL-EVIL 

tion. The disease being left to effect incurable 
damage to the bones, particularly to the occipi- 
to-atloid articulation, can not be cured entirely 
by simply resecting the ligament. Where the 
ligament is removed early failures are negligi- 
ble. Recurrences are due to sloughs of the dis- 
tal stump referred to above or to failure to 
remove all of the ligament. 

By avoiding old incurable cases, by resorting 
to effectual restraint and anesthesia, by op- 
erating deliberately and without delay, by at- 
tending skillfully to the wound and by keeping 
in mind the slough of the distal stump, the r?o- 
ical operation for poll-evil is attended wi* .i 
few failures. It should be a routine measi^e 
with every veterinary practitioner. 

And what is writ is writ; 

Would that it were worthier. — Homer. 

THE END 



